Chromogenic glazing

ABSTRACT

A transparent chromogenic assembly in which color changes are selectively effectable over predefined areas comprises a pair of facing transparent substrates ( 15, 21, 28 ) each covered with a conductive layer divided into individual energizeable areas each provided with a set of busbars ( 187, 188 ). A passive layer may be superimposed over one of the substrates, its color being chosen so that the color and the transmissivity of the passive layer accommodates the range of color change and transmissivity of the electrochromic layer to maintain the transmitted color of the panel in a warm or neutral shade. Various other chromogenic windows, devices and systems are also disclosed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to glazing and, more particularly, tochromogenic glazing for use in applications, such as automobiles anddisplay filters, where it is desirable to reversibly alter thetransmission or tinting of the glass. This invention may also be usedfor other means of transportation glazing such as trucks, buses, boats,planes, trains, etc. and also in building glazing.

[0003] 2. RELATED BACKGROUND ART

[0004] Automobile windshields, movable and fixed side and rear windows,and divider panels between the front and the rear cabin, as well assunroofs, employ various forms of glazing in a variety of colors andintensities. Typically, when tinted glazing is employed, the windshieldand the front side windows are clear for safety reasons. Car glazing mayprovide for management of both ultra-violet and infra-red solar energypenetration to enhance user comfort while reducing the powerrequirements for air-conditioning. Besides the need to carefully controltinting so that glass used in adjacent windows does not appear to bemismatched, it is important to consider the effect that glazing colorcan have on passengers' skin tones. For example, some colors, such asdeep violet glazing may make the interior colors appear dull and/orstrange and cause the skin tones of passengers to appear unnatural.

[0005] To adapt chromogenic glass, i.e., glass that hasuser-controllable transmissivity (for example see U.S. Pat. No.6,039,390, which is incorporated by reference herein, for varioustechnologies for user-controlled glass transmission, all of which areapplicable here) for use in automobiles, it is important that the glassexhibit several characteristics:

[0006] 1. Chromogenic glazing should be compatible with the color of thecar's interior.

[0007] 2. Chromogenic glazing should be available in “warm” tones and in“neutral” tones.

[0008] 3. Chromogenic glazing should not acquire an unacceptable colorwhen it is changed from clearer to a darker state under user control.

[0009] 4. Chromogenic glazing should maintain an acceptable colorappearance from the outside, e.g., it is preferable that all of thewindows should have similar color properties while permitting the depthof coloration of the windows (and of the sunroof) to vary.

[0010] 5. Chromogenic glazing for use in a windshield may be colored orbleached to a different shade or color as compared to the other windowsto maintain safe, non-glaring conditions during driving.

[0011] 6. Chromogenic glazing should maintain a desired state of colorwithout consuming too much battery power when the vehicle is parked fora long period of time.

[0012] Problems With Prior Art Chromogenic Glass

[0013] When a formulation for chromogenic glass is adopted, considerablethought is given to selecting and processing the materials in order forthe glass to meet a desired transmission range, durability andenvironmental resilience, i.e., performance over a range of temperature,typically between −40 to 100C, varying humidity, and solar radiation.Electrochromic (EC) devices used in automobile glazing should not drainthe battery even when left parked in the darkened state. In automobileglazing the aesthetics of color choice play an important role.Automobile manufacturers currently prefer glazing colors that are“neutral” or “warm” so that the flesh tones of the driver and passengersand the interior colors will not be cast in an unappealing light.Certain EC materials, such as those that derive their color principallyfrom tungsten oxide, can typically color to a blue tint and maybeundesirable in some circumstances because their color change fails tomeet the neutral/warm criteria. To meet the desired characteristics,such EC materials must be modified by doping, so that they will color toa more neutral shade, but in doing so the coloration range may becompromised. Other compromises made in material selection may affectdurability because of electrochemical changes in the material. Inaddition, glazing used in an automobile windshield may need to havedifferent transmissivity and color characteristics as compared to theside or rear windows and sunroof. While some chromogenic devices may beavailable that change to a more neutral color, they may not conform tothe desired transmission range required for the various locations. Thechemical modification of such materials to meet these diverseapplications is a daunting task.

[0014] It is therefore an object of the present invention to accommodatethe different “tunability”, “transmissivity” and environmentalattributes required of glazing destined for diverse applications,without entailing the time and expense required to formulate a new ECmaterial having the desired characteristics.

SUMMARY OF THE INVENTION

[0015] The above noted problems of chromogenic glass for use in variousglazing applications are solved in accordance with the principles of thepresent invention by providing a transparent chromogenic assembly inwhich color changes are selectively effectable over predefined areas ofthe assembly that comprises a pair of facing glass substrates separatedby an electrolyte. A conductive transparent coating is deposed on facingsurfaces of the substrates, the conductive coating of at least one ofthe surfaces being interrupted to define individual areas each of whichis provided with a set of busbars, advantageously of silver frit. Anelectrochromic electrode layer overlies at least one of the conductivelayers. An insulating adhesive sealant spaces apart the substrates andinsulates the busbar sets from each other and from exposure to theelectrolyte and the electrochromic layer, so that each busbar set may beindividually energizeable to effect a color change through a respectiveone of the individual areas. Advantageously, the electrochromic layermay comprise a transition metal oxide or a mixture containing at leastone transition metal oxide, preferably tungsten oxide, while acounterelectrode layer on the facing surface may comprise an oxide ormixture of oxides. A preferred mixture has at least three oxides,preferably two of the three oxides are transition metals and one of themis an alkali metal. A portion of each busbar advantageously extends fromthe facing surface to and over a respective edge of the substrate toform a connector for the terminal electrode that provides exceptionalmechanical stability.

[0016] Further in accordance with the invention, it is important toselect those attributes which allow chromogenic devices to exhibit lowleakage currents, e.g., by employing inorganic EC and counterelectrodesthat are selected principally from the transition metal oxides, examplesbeing at least consisting in part of tungsten oxide, molybdenum oxide asEC electrodes and consisting in part of vanadium oxide, nickel oxide,manganese oxide, niobium oxide and titanium oxide for counterelectrodes, and by using sulfolane or its derivatives in full or part asthe solvent and/or plasticizer in the electrolyte when a solid polymermatrix electrolyte is used. Further, the water content of theelectrolyte is preferably lower than 2000 ppm, more preferably lowerthan 100 ppm and most preferably as low as 10 ppm. The EC and thecounterelectrodes may be further doped by alkali metal oxides such asLi, Na, Ba, Ca, K, Cs and Rb oxides.

[0017] According to another aspect of the invention, in one illustrativeembodiment, a transparent chromogenic assembly is provided whichcomprises an active component layer and a passive component layer inwhich the active component layer is selected from the group consistingof electrochromic, liquid crystal, user-controllable-photochromic,polymer-dispersed-liquid crystal or suspended particle devices and thepassive component layer is selected from the group consisting ofsubstrates or covers for the active layer, the active and the passivelayers being chosen so that the color and the transmissivity of thepassive layer accommodates the range of color change and transmissivityof the active layer to maintain the transmitted color of the assembly ina warm or neutral shade, where warm colors correspond on the L*C*h colorsphere scale to C having an approximate value between 15 and 45,preferably between 18 and 30; h having a value between 20 and 115,preferably between 40 and 100, and L having a value dictated by thedesired degree of glass darkness or preferred degree of photopictransmission. A preferred counterelectrode composition consists of Li,Ni and Mn oxides to facilitate obtaining the desired color change as anintrinsic attribute of the EC device.

[0018] Yet another embodiment of this invention is directed to achromogenic device with controlled variation of the area subject tocoloration. This device includes a pair of facing transparent substratesdefining a cavity enclosing an electrolyte medium. Each of the facingsurfaces of the substrates has a conductive transparent coating. Inaddition, an electrochromic layer is disposed on at least one of theconductive transparent coatings. Significantly, each conductivetransparent coating will have at least two bus bars in contact therewithand the two bus bars are positioned in a spaced-apart relationship thatdefines a portion of the device in which the area of coloration of thedevice is variably controlled. Of course if the chromogenic deviceincludes two or more portions as in the previously described chromogenicassembly, one or more of those portions may be designed to allowcontrolled variation of the area of each portion subject to coloration.The chromogenic device will also include a controller that provides ameans for controlling the area of coloration by varying a voltage dropacross the portion of the device being controlled. The controller willgenerally include a switch for applying a voltage between a first ofsaid two bus bars contacting a first of the transparent conductivecoatings and an opposing first of said two bus bars contacting a secondof the transparent conductive coatings. The controller will alsopreferably include a variable resistor communicating between a second ofsaid two bus bars contacting the first transparent conductive coatingand a second of said two bus bars contacting the second transparentconductive coating. In a preferred embodiment, the area of the portionof the device subject to coloration may be controlled by varying theresistance value of the variable resistor.

[0019] Another embodiment of this invention is directed to a chromogenicdevice having both coloration and heating capability. This device issimilar in structure to above described device that provides forcontrolled variation of the area of coloration, but its controllerprovides a means to selectively apply a voltage to color the device orheat the device. Preferably, the controller of this device includes anelectrical circuit that may be selectively controlled (i) to causecoloration of the device by creating a voltage potential between atleast one of said bus bars contacting a first of the transparentcoatings and at least one of the two bus bars contacting a second of thetransparent coatings and (ii) to cause heating of the device by creatinga voltage potential between at least the two bus bars contacting atleast one of the conductive transparent coatings. Of course, ifdesirable a controller may be fashioned to provide the ability to heatthe device, color the device and provide control of the area of thedevice subject to coloration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The foregoing and other features of the present invention maybecome more apparent when the ensuing description is read together withthe drawing, in which

[0021]FIG. 1 shows plots of the transmissivity (T) of various glassesover the range of visible wavelengths;

[0022]FIGS. 2A and 2B depict respective isometric views of portions ofthe facing substrates while FIG. 2C shows a cross section A-A viewthrough an illustrative EC assembly according to the invention;

[0023]FIG. 3A depicts an isometric view of an alternative embodiment ofone substrate;

[0024]FIG. 3B shows a similar cross section-through the alternativeembodiment; employing substrate of FIG. 3A, and

[0025]FIG. 4 shows a cross section through a further alternativeembodiment.

[0026]FIG. 5A illustrates an exemplary single substrate with atransparent conductor and busbars that may be used in the chromogenicassembly of this invention.

[0027]FIG. 5B illustrates yet another exemplary single substrate with atransparent conductor and busbars that may be used in the chromogenicassembly of this invention.

[0028]FIG. 6 shows the conductive substrates of a chromogenic assemblythat are split apart for illustrative purposes.

[0029]FIG. 7 illustrates a control panel that may be useful incombination with an automotive vehicle having electrochromic glazing.

[0030]FIG. 8 illustrates an electrochromic front side window of thisinvention having a separate electronic controllable partition thatcorresponds to the area through which the side view mirror is observed.

[0031]FIG. 9 shows a substrate that may be used in an electrochromicdevice of this invention and which renders the device capable of heatingthe substrate.

[0032]FIG. 10 illustrates a side view of an electrochromic devicecapable of being used as a heater.

[0033]FIG. 11 is an electrical schematic diagram that illustrates acircuit diagram for controlling an electrochromic/heater device.

[0034]FIG. 12 illustrates an electrochromic device of this inventionhaving both electrochromic and heating capabilities.

[0035]FIG. 13 illustrates an electrochromic device of this inventionhaving a shad band area that is controlled by the resistance between theelectrodes.

[0036]FIG. 14 illustrates a large window with independently poweredchromogenic panels tied to an image sensor located on a wall opposingthe window.

[0037]FIG. 15 illustrates a large area window comprised of a pluralityof chromogenic panels wherein selected panels have been darkened toresult in a desired image.

[0038]FIG. 16 illustrates a block diagram of a system for controllingthree chromogenic windows by individual image sensors that communicatewith the individual power supplies/controllers of the windows through acentral management system.

DETAILED DESCRIPTION OF THE INVENTION

[0039] As pointed out in PCT application WO 98/08137 and in WO 99/09112,the disclosures of which are hereby incorporated by reference,chromogenic members may be made by a variety of techniques includingelectrochromic materials, liquid crystal technology, user-controllablephotochromic, polymer dispersed liquid crystal, incorporation ofsuspended particles, etc.

[0040] To achieve the degree of tunability in color and transmissivitydesired for automobile glazing, a colored substrate layer may becombined with a layer of EC material or an exterior non-chromogeniccover may be used over the EC material. Typical practical chromogenicdevices for this purpose will have a contrast ratio (ratio of bleachedto colored transmission) from about 2:1 to about 20:1, preferably about3:1 to about 20:1. The contrast ratio is typically measured usingphotopic transmission or total solar transmission. A colored substratelayer added to the EC layer balances the different needs for shading,privacy, clarity, UV and IR blocking that arises in different types ofautomobiles and at the different glazing locations in the same car. Thecolor of the substrate or of the cover glass should preferably beneutral or should be chosen so as to bring out a “warmth” quality of thecolor and be synchronous with the car exterior. When a colored glass isused it is preferable to mount the EC so that the colored substrate orcover is facing the exterior of the car so that some or considerableamount of the solar energy is absorbed by the outer glass, firstly toprovide UV barrier and secondly to reduce the temperature rise of the ECpanel due to energy absorption.

[0041] An EC device according to the invention may be made using clearsubstrates that are laminated (e.g., using poly vinyl butyral, polyvinylchloride or polyurethane, or another plastic sheet etc.) to a coloredglass sheet. Tint and UV blockers may be incorporated in such a plasticsheet. See, U.S. Pat. No. 6,122,093, the disclosure of which isincorporated by reference herein. However, if such a sheet is colored,then a clear glass may also be substituted for the colored glass.

[0042] Using an Appropriate Substrate

[0043] As described above, one of the substrates, or the cover glass,should preferably bring out warmth in color or be neutral. If the ECdevice in the bleached state does not have substantial color, any kindof cover glass will impose its own coloration. Thus, if a particular ECdevice goes from colorless to blue, then a brownish (or warm) cover willallow the device to perceived as being warm in the bleached state andbeing near neutral in the colored state because brown is a complimentarycolor to blue.

[0044] However, if a 20% transmitting gray colored exterior cover isused, for example, in a sunroof, the sunroof will always be perceivedfrom the outside as being gray during the daytime regardless of thecolor of the EC panel inside. Thus, the color of the outer glass and itstransmittance may solely determine the appearance of the glass fromoutside for a sunroof during the day. Colors with warmth are describedbelow.

[0045] Warm colors on an L*C*h color sphere scale correspond to Cbetween 15 and 45, and h between 100 and 20, while L depends on thedarkness of the glass or preferred degree of photopic transmission.Neutral colors correspond to C less than 15, preferably less than 5, andh between 0 and 360, while L can be any number within the desiredphotopic transmission as given below. The color can also be expressed onother scales, such as CIE (Y, x, y), or L*a*b, etc. For convenience, theL*C*h scale will be used herein. The “C” and “h” in the L*C*h arerelated to “a” and “b” in the L*a*b scale by:

C={square root}V(a ² +b ²) and h=tan⁻¹(b/a).

[0046] For the darker windows, including the sunroof, it is preferredthat the bleach transmission should be in the range of 15 to 70% andmore preferably in the range of to 35% photopic transmission (i.e.,transmission measured over the range of visible wavelengths), althoughthe solar transmission could be different. This range of transmissionprovides sufficient privacy during daytime when viewed from outside,provides a clear view from inside and allows entry of sufficientdaylight to the interior. In the colored state, the preferred photopictransmission range is below 10% and most preferably below 5%. Forwindshields and front side windows which, preferably, do not use coloredglass, the preferred photopic transmission should be greater than 70% inthe bleached state to comply with federal safety specifications formotor vehicles. Further, the haze of such windows should be lower than5%, preferably lower than 2%, more preferably lower than 1% and mostpreferably lower than 0.5%. To avoid direct glare from the sun duringthe day and make driving safer, the photopic transmittance ofchromogenic windows in this application in the colored state should belower than 35%, preferably lower than 20% and more preferably lower than15%. While there is no generally accepted specification for minimumtransmission, it is reasonable to set a photopic transmission level thatis analogous to that of sunglasses where a photopic transmission in therange of 5 to 20% is usually employed.

[0047] A substrate for chromogenic glass can be made in different waysto have the preferred color and can be tempered and coated withtransparent conductors, such as indium tin oxide by sputtering or bychemical vapor deposition of fluorine doped tin oxide on a glass floatline such as used in the manufacture of Sungate 500. PCT application WO98/08137 describes several constructions of chromogenic devices usingvarious substrates and the use of an outer glass is used to mask theinner chromogenic glass.

[0048] EC devices can be made from commercially available cleartransparent conductors. The outer glass could have the desired warm orneutral color. If the EC device is clear (not colored) in the bleachedstate, then a warm colored cover will result in a warm color beingperceived by the viewer. If the EC colors blue, then a warm color suchas brown (which is approximately complimentary to blue) will result in aneutral color being perceived. However, it is not only the color of thefilters, which are combined, but also how deep the coloration is. Forexample, if deep blue is combined with light brown, the composite maystill be perceived as blue.

[0049] Warm colors are typically bronzes, brown, gray-brown andgray-bronze. Glass in these colors are made by several manufacturers. Asan example PPG (Pittsburgh, Pa.) has several glasses both coated andbatch, some of these along with their transmittance specifications are:Solarbronze tinted (52% visible and 46% solar transmittance), Sungate300 Solarbronze (Visible 44% and 30% solar transmittance), Sungate 300Solarcool Bronze (18% visible and 19% solar transmittance) andOptibronze (29% visible and 20% solar transmittance in 4 mm thickness).Such glass is made by coating glass or adding additives to glasscomposition so that it acquires this color, called batch glass. Sincethe coatings could scratch, preferred glass for automotive applicationis made by batch processes. Laminating a colored plastic sheet betweentwo glass panels could also make glass with an acceptable color.Examples of neutral colored glasses are GL20 and GL35 from PPG. Theirspecifications of photopic transmittance are 20% and 35% and their Solartransmittance are 16 and 29% respectively in 4 mm thickness. TheirL*C*h* values and photopic transmittance was measured in our laboratoryusing a Hunter Lab Ultrascan XE instrument (Reston, Va.). According tothe lab measurements the L*C*h value of GL-20 were <L*C*h* 47, 0.94,243> and photopic transmittance was 16%. For GL-35 these numbers were<L*C*h* 66, 1.6, 125, and photopic transmittance of 35%. It is notnecessary that all substrates have to be bulk glass, they can be glasslaminated with the plastic inner layers (laminating layers such as polyvinyl butyral, polyurethane, polyester, vinyl, etc.). These plasticsheets may be optionally tinted to obtain the desired color as well.

[0050] An EC sunroof which uses Optibronze (L*C*h* 59, 23, 73) as theexterior glass cover in combination with an EC device underneath it willhave a warm color in the bleached state as long as the interior EC paneldoes not contribute to the color too strongly. The photopic transmissionof the Optibronze sample measured in our laboratory was 27%. The ECdevice can color to a different color, e.g., to a blue color or a greencolor. For the blue coloring EC panel, the passenger inside the car willperceive that the sunroof is coloring to a gray (neutral color).

[0051] For car glazing, the outer panel, if separate from the interiorEC panel, should preferably block the UV. This could be the outer panelof the EC device or be only a cover glass as described above. The outerglass should block the UV and have an absorption edge between 320 and400 nm. Absorption edge (i.e., wavelength λ) means that as thewavelength of the light is decreased from the visible into the UV, thepanel should start absorbing the light increasingly and that itsabsorbance should reach 2 at this λ.

[0052] The desired degree of absorbance characteristic within the ECdevice can be obtained by appropriate doping of the tungsten oxidepreferably with other oxides. Also, the electrolyte may be modified byadding UV absorbers. However, another effective way, without modifyingthe device, is to block UV external to the EC device. This can be doneby using a substrate which is UV blocking and/or a cover which blocksthe UV. Absorbance is the logarithmic (to the base 10) ratio ofuninhibited intensity of light to the intensity of such a light beamafter it passes through the substrate. An absorbance level of 2indicates that the glass at that wavelength is only allowing 1% of theincident light to pass through. The wavelength, where the absorbancereaches 2 is defined as the absorption edge. For use in automotiveglazing, below the absorption edge (λ) the glass should continue toincrease in absorbance or maintain this level of absorbance up to 290 nmor lower wavelengths.

[0053] Referring now to FIG. 1, the transmissivity and absorbance ofseveral glasses are shown. GL20 glass and Optibronze have an absorptionedge at 350 nm, and GL 35 has an absorption edge at 340 nm at athickness of 4 mm. The absorption edges for both are very sharp, in thatthat they reach an absorption value of almost 5 at 340 and 330 nmrespectively. These glasses also retain absorbances of greater than 5 atleast down to 290 nm and Optibronze retains its absorbance of greaterthan 5 down to at least 200 nm.

[0054] When multiple substrates are used, such as separate cover over anEC panel separated by vacuum, air, krypton, argon or other gases, itwould be beneficial to further coat the surfaces of the cover and the ECdevices with low-e and/or anti-reflective (AR) coatings. Low-e coatingswould enhance the energy efficiency of such glazing and the AR coatingswould reduce multiple reflections and hence increase optical clarityfrom the various surfaces in contact with air, vacuum or gases. As anextension of the technology, at least one of the substrates or the coverglass may be made out of a photochromic material to provide extra depthof darkening that would be a useful addition under bright conditions tothe darkening effected by the chromogenic device. This method can alsobe used in non-glazing applications such as eyewear. The preferredcolors for such photochromic substrates are browns (warm) and grays(neutral). Exemplary plastic photochromic substrates include thoseavailable under the tradename Transitions™ manufactured by TransitionsOptical, Inc., Pinellas Park, Fla. and exemplary glass substrates arePhotoGray Extra®, PhotoBrown Extra®, PhotoSun II® manufactured byCorning, Corning, N.Y.

[0055] In addition, the EC systems for the front-side windshield and thefront automotive windows (called frontal windows) could be differentfrom the others which may include the sunroof, in terms of the EC devicetype. For example, The EC device configuration could be different sothat higher optical transmission through the frontal windows isobtained. The difference in the transmission may be caused by tintingcomponents (glass electrolytes, additional coatings) as described above,or it may be because simply a different layer thickness for EC and othercoatings (transparent conductor, counter electrode, etc.) may beemployed. Specifically, a device consisting of tungsten oxide (includingdoped tungsten oxide), and a counter-electrode (such as nickel oxide,doped nickel oxide, vanadium oxide, doped vanadium oxide, iridium oxide,polyaniline) may employ a 200 nm or thinner tungsten oxide and a 100 nmor thinner counter-electrode for the frontal windows, and thickercoatings for the others, such as 400 nm or thicker tungsten oxide and200 nm or thicker counter-electrode. Similarly, a difference may alsoexist in the thickness of the transparent conductor as well. The lowerlayer thickness will result in higher bleach state transmission of thefrontal windows, however, it may not have as high a contrast ratio asthe other windows. A preferred ratio of layer thickness of at least oneof the layers of the EC system between the frontal and the other windowsis less than or equal to 0.5. The advantage of using the same materialsis that all the windows can be processed using same materials on thesame processing line with only changes in parameters which control thethickness. Another advantage may lie in the control system where similarvoltages and voltage range could be used to control all glazing.Further, this is also advantageous if one wished to have similar colorsand color change for all windows.

[0056] Using an Appropriate Substrate Coating

[0057] Another way to select the substrate materials is where the colorprimarily arises due to the coatings beneath the transparent conductivecoating. Since, the transparent conductor faces inside the EC device,and most kind of chromogenic devices require two substrates, the coloredcoatings cannot be scratched during the use. One such substrate is SolarE from LOF (Toledo Ohio).

[0058] Using Appropriate Active Materials

[0059] One can also obtain the EC devices that color to a warm tonewithout the use of colored substrates, i.e., by using active materials(electrolyte, EC and counter electrodes) in the electrochromic deviceswhich result in this color. Such embodiments are shown in FIGS. 2Athrough 4. When the EC devices are made by using two substrates, 10, 20facing each other with an electrolyte 29 “sandwiched” between them onecould use a permanent color in the electrolyte to generate the requiredcolor in the bleach state. For those EC devices where a chromogeniccoating and/or counterelectrode 19, 28 (see FIG. 2C), is required, onecould select materials so that the desired color is achieved. Forexample it was discovered by experimenting in the laboratory that whenthe typical blue coloring tungsten oxide was used for chromogeniccoating, e.g., 28 on one of the substrates, e.g., 20, and combination ofmetal oxides was used for the counter electrode, e.g., 19 on substrate10, the resulting EC device had the warm color. The transparentconductive substrates 15, 21, 28 and the electrolyte 29 used were clear.The composition of the counterelectrode 19 contained manganese oxide andor nickel oxide. Manganese oxide has different colors depending on itsoxidation state, e.g., MnO is green, Mn₂O₃ is black and Mn₃O₄ is purplered. However, hereinafter for convenience, reference will be made to theoxide as “MnO”, without mentioning the valence state of manganese. Itshould be understood that any of the valence states may be employeddepending on the color desired. The manganese oxide coatings, whenincorporated into the counter electrode of the EC cells (with tungstenoxide being employed in the EC electrode), exhibited the warm color.Preferred oxides as additives to this mixture for the counterelectrodewere oxides of Li, Na, K, Ni and Co. Manganese oxide must be present inthe counterelectrode so that the Manganese is at least 20 atomic % ofall the other metal cations (excluding hydrogen which may be present aswater or as OH groups).

[0060] Further, the tungsten oxide used as the chromogenic layer 28 inthe above devices could itself be doped with oxides of Li, Na, K orother oxides to impart desirable characteristics to the device. Forexample, pending patent application Ser. No. 09/443,109 gives severalexamples of how tungsten oxide could be doped by other oxides to impartUV resistant characteristics. This reference is incorporated herein byreference. When the device colors, the tungsten oxide coating colorsblue but the device color changes from light bronze to blue-bronze orgray. However, if the tungsten oxide coating colors neutral (such as fordoped tungsten oxide in U.S. Pat. No. 5,847,858, WO 99/08153 and patentapplication Ser. No. 09/443,109, then more of the bronze or brown colorwill be retained in the colored state of the device as well. For theabove doped neutral coloring tungsten oxides one could additionally usethe preferred dopants such as oxides of Cr. Co, Cu and P as described inthe aforementioned patent application to give them enhanced UVresistance. Different tungsten oxides can be used and many of them candoped to give different colors such as from blue to neutral gray. Hereit should be noted that Cr, Cu and Co, etc described in our patentapplication Ser. No. 09/443,109 may also be added to these compositions.

[0061] Another important aspect for the chromogenic glazing of cars isits ability to maintain a desired state of color without consuming toomuch battery power. When the vehicles are parked for long periods oftime this can lead to severe battery drainage and cause inconvenience tothe user. Also, for several types of chromogenic devices, particularlyfor the EC devices the change in transmission set by the user and theaccompanied charge consumed by the device tend to increase withincreasing temperature. Our analysis shows that the chromogenic windowsin cars parked in direct sunlight may heat up to 65 to 95° C. in hotsummers in many parts of the world. Thus the chromogenic glass shouldtypically consume low power and hold their transmission when subjectedto these temperatures. Some type of devices using specific liquidcrystals and suspended particles may not even have the required contrastat these temperatures, as discussed earlier the minimum photopiccontrast (ratio of bleached to colored state) should be 3:1. Thus for aglazing to be useful, it must meet the colored and transmission levelsdescribed above and consume low power. For cars and those applicationswhich have large window areas and depend on battery power, the change inphotopic transmission at a temperature of 85-105° C. should be less than10% in fifteen minutes, and preferably less than 2% when the poweringvoltage is removed. To maintain a constant transmission, the power canbe applied continuously or intermittently. Various ways to powerchromogenic devices is explained extensively in the patent applicationSer. No. 09/347,807.

[0062] Alternatively, at this temperature the average leakage current(averaged over time) to maintain a constant transmission should be lessthan 10 μA (micro-amp)/cm², and more preferably 1 μA/cm², and mostpreferably less than 0.1 μA/cm². It is not uncommon to see the leakagecurrent over the active electrochromic window areas increase by a factorof ten or more at 85° C. when compared at room temperature (nominally25° C.). There are several ways to reduce the drain on the battery, suchas the use of supplementary power sources (meaning other than the mainbattery powering the automobile) including Solar cells; Joule-Thompsoneffect (thermoelectric) based electric generators and auxiliaryrechargeable batteries. Also more efficient power circuits such as thoseusing switching power supplies can be used to step down the voltage moreefficiently. However the most preferred device would be one in which,intrinsically, low power is consumed by the EC device for a costeffective solution and, advantageously, any of the above may be combinedtogether to achieve low leakage current. Also, sensors and sleepcircuitry may be employed to keep the average current consumption withinlimits. One way is to sense by a photo-sensor when it is nighttime, andif the car is parked then to automatically turn the power off to thechromogenic system when the ignition is turned off, simultaneously orafter a pre-set time. Next day, when the sun comes out, the chromogenicwindows can again be energized. This sequence can be continued overseveral days, and then the sleep circuitry (if used) can take over wherethe power is cut off to the chromogenic system until the user returnsand starts the car. Chromogenic panels for automotive and otherapplications where conservation of battery power is important should notrequire an average current exceeding 10 μA/cm² of active area over an 8hour period at 85° C. to maintain a particular state of coloration.

[0063] Chromogenic Construction

[0064] Chromogenic windows may be installed as separate members andframed together as one large window or a unit. However in doing so, dueto individual seals, busbar areas and play between different sectionsone could loose visual area. For example when framing is used to puttogether windows for architectural use (skylights, windows, etc) or fortransportation (windows in cars, planes, boats, buses and trains, etc.)the width of the frame in which these sections are accommodated can betypically 0.5 to 2 inches wide (referred to as the non-active area).Also for chromogenic devices, particularly for the EC devices, as thesection size in each window increases, in typical constructions theirkinetics (speed to color and bleach) will decrease. One way to eliminatethe slowdown is by the use of internal busbars as discussed inapplication Ser. No. 09/347,807.

[0065] In many situations it is desirable to have sections ofchromogenic panels which are independently controllable withoutincurring the penalty of excessive “dead” (inactive) areas caused by theneed to have a frame around each area. FIGS. 2, 3 and 4 show severalways in which it is possible to achieve multiple sections in amonolithic device in which the width of the non-active area issignificantly reduced; e.g., a typical range may be 0.01 mm to 10 mm, orpreferably between 0.1 to 5 mm. However, the separation between activeareas (which is achieved by the interruption or deletion of thetransparent conductive coating as, for example, by etching) shouldpreferably be wider than 0.1 microns to provide adequate electricalisolation. As an example in a car sunroof, one may partition a monolithchromogenic device in two so that each of the driver and the passengercan independently control the tint of a respective portion withoutdiminishing the expanse of the sunroof by the need to use individualframes for each portion. In addition, each sunroof section may even betied to separate air-conditioning system so that, depending on thechoice of the passenger and driver, the tint of the panel on top oftheir bodies will be synchronized with their individual temperatureand/or shade preferences.

[0066] Another advantage of partitioning without the need for individualframes is that cost is reduced. For example, for a skylight of abuilding one may produce four separate EC panels say 1 ft×1 ft (30.5cm×30.5 cm) in size and frame them together to yield a 2 ft×2 ft (61cm×61 cm) EC panel. These could then be installed in the skylight forexample, as described in the WO 98/08137. Alternatively, in accordancewith the framing elimination concept of the present invention, one maystart with 2 ft×2 ft (61 cm×61 cm) substrate, and divide the conductivearea in four equal square parts by etching away the transparentconductive coating preferably to a width of at least 0.1 microns. Thisalternative construction achieves the performance of separately made orframed panels, but at reduced cost. For example, a skylight ofsignificantly larger size and superior performance can be fabricatedusing only two substrates and one set of wiring rather then eight orfour sets, respectively, where it is not necessary that each of theskylight cells needs to be independently controlled. If, for aestheticreasons, it were desired to provide a “framed” appearance, any number ofcosmetic dividing bars of any desired width could be used over themonolithic construction without incurring the cost penalty necessitatedby prior art individual frame construction of the separate EC panels.Internal busbars may be included in the interior of each of thepartitioned areas to give faster response.

[0067]FIGS. 2, 3 and 4 show electrochromic devices which utilize an ECand a counterelectrode, however the principals of this construction canbe used for any type of EC devices, suspended particle devices, etc.FIGS. 2, 3 and 4 are not drawn to scale. In FIG. 2A, a substrate 10,typically glass, forms the top of an illustrative assembly according tothe invention together with a bottom substrate 20 which is shown in FIG.2B. FIG. 2C is a cross sectional view, A-A′, of the composite assemblyshowing the respective EC or counter electrode layers 28, 19, theinsulating spacer/sealant element 27 and an electrolyte 29. Referring toFIG. 2A the upper substrate 10 has deposited thereon a conductivetransparent coating 15 (illustratively, tin oxide or Indium tin oxide)which functions as a counter electrode. In addition, a layer 19 may bedeposited over the conductive coating 15 and layer 19 may be chosen ofmaterials that exhibit EC behavior if desired.

[0068] As more clearly shown in FIGS. 2B, 2C and 3A, the upper and lowersubstrates are provided with highly conductive busbars, advantageouslyof silver frit, deposited over the transparent conductive layer, forexample by silk screen process. It is preferred that the busbarssurround at least 3 sides of the periphery of the transparent conductivelayers. Thus, substrate 10 has quasi-peripheral busbars 17, 18 andsubstrate 20 has quasi-peripheral busbars 22, 24 while substrates 30 and40 of FIGS. 3 and 4 have busbars 32 and 34 and 47 and 48 that surroundall four sides of the associated transparent conductive layer. Use ofthe busbars provides for more even application of current so that afaster color change will be produced throughout the EC layer whenelectric currents are applied. Referring to FIGS. 2B and 2C it ispreferred that a portion of each busbar 22, 24 extend from the facingsurface of the substrate to and over a respective edge to form arespective connector portion 23, 23′ to facilitate the attachment ofterminal wires 11, 11′, illustratively by soldering. To facilitateconnections, connectors 23, 23′ are advantageously located at edges 23′of the lower substrate 20 that are diagonally opposite to the locationsof the connectors 13, 13′ of the upper substrate 10. It is important toprotect the electrodes from corrosion, particularly in the presence ofwater by encapsulating or shielding them with non conductive adhesives.

[0069] Advantageously a tungsten oxide containing electrochromic layer28 on the lower substrate 20 may be used together with a LiNiMnO orvanadium oxide (including mixed oxides with vanadium oxide being one ofthe constituents) counterelectrode layer 19 on the upper substrate 10 tofacilitate obtaining the desired color change as an intrinsic attributeof the EC device.

[0070] With respect to lower substrate 20, the transparent conductivelayer corresponding to the upper transparent conductive layer 15 issplit into two segments, 21 and 21′ so that the hue and/or density ofcoloration produced in the left and right hand portions of the assemblymay be separately controlled by potentials applied between wires 11 and26 at the left and between wires 11′ and 26′ at the right. It is thus anadvantage of the illustrative construction that color difference betweenleft and right hand sections may be obtained with minimum “non-activezone” separation between the EC active elements, a separation dictatedby the thickness of dividing line 25-25′ which separates the transparentconductive layers 21, 21′ while the counter electrode layer 19 and theEC layer 28 may be continuous. As mentioned above, layer 19 may alsoadvantageously exhibit EC characteristics if desired.

[0071] In FIG. 2C the electrolyte 29 is shown sealed between substrates10 and 20 by means of peripheral seal/spacer element 27 which isadvantageously black in color and which protects and insulates busbars22 and 24 from electrolyte 29 and from EC/counter electrode layer 19 ofthe upper substrate 10 and from the electrolyte 29 and the EC layer 28of the lower substrate 20. Connectors 13 and 13′ connect wires 11 and11′ to transparent conductive coating 15 of upper substrate 10 by makingcontact with bus bars 17 and 18 respectively. Although shown as separateelements in the drawing, it should be understood that connectors 13 and13′ may in practice be formed by extended respective portions of busbars17 and 18 from the facing surface of substrate 10 to its left- andright-hand edges. Having the connector portions extend to the edges ofthe substrate yields more surface and greater mechanical stability foreffecting the soldering of wires 11, 11′ to connect to the conductivetransparent layer 15. Similar remarks apply to wires 26 and 26′ andconnectors 23 and 23′ of lower substrate 20.

[0072] Referring now to FIG. 3A a substrate embodiment alternative tothat of FIG. 2A is shown in which the busbars 32 and 34 substantiallycompletely surround the periphery of the left and right hand colorablesections of the lower substrate. FIG. 3B shows a cross sectional view ofan assembly in which busbars 32, 34 of upper substrate 40 and busbars47, 48 are of the type generally shown in FIG. 3A are employed. Toprotect those sections of busbars 32, 34 and 47, 48 not otherwiseshielded from contact with electrolyte 29, a passivation coating 32C,34C and 47C, 48C is applied to these portions.

[0073] Passivation materials used are those which do not participate inany electrochemical reaction and do not conduct ions. It is furtherpreferred that these are also electronically insulating (unless they areelectrochemically inert oxide conductors such as Indium/tin oxide, dopedtin oxide, doped zinc oxide and ruthenium oxide). It is also preferredthat they have good adhesion to the underlying layers which areprincipally frits, conductive metal and ceramic lines and thetransparent conductors. If solid or liquid electrolytes are used it ispreferred that they have good adhesion and wetting respectively. Someexamples of these are epoxies, urethanes, silicones and acrylicadhesives and lacquers, which do not contain any conductive fillers.These can be one part or multi-part formulations. They can be thermosetsor thermoplastics. They may have adhesion promoting agents such assilanes which are common in the adhesive industry. Further thepassivation layer may not be a single layer but multiple layers, e.g.,the first layer could be a silane primer or something else to promoteadhesion, and the second layer could be one of the materials describedabove. Other than the class of materials described above these can alsobe inorganic oxides, or organic-inorgainc hybrids. An example of thefirst one is silica, alumina, etc, and of the second where suchmaterials are modified by organic moieties. These layers can bedeposited by screen-printing, photolithographic processes, dispensing,wet-chemical deposition (e.g., silica using alkoxides such as tetraethyl ortho silicate, colloids, etc.), sputtering, evaporation, chemicalvapor deposition, etc.

[0074] In FIG. 4 a similar construction to that shown in FIGS. 3A and 3Bis depicted, however, instead of a passivation coating being used onsections of the the busbars that would otherwise be exposed to theelectrolyte, a comprehensive peripheral sealant 50, 51 is used. Thishowever has the disadvantage that the separation between colorablesections of the assembly may have to be wider because of the thicknessof the sealant along the separation line 35, 35′.

[0075] It should be realized that while flat substrates are shown in thedrawing for purposes of simplicity, substrates may be curved toaccommodate a desired automobile appearance. There are severalchromogenic constructions and methods to make such glazing. For examplea car sunroof can consist of an outer panel with one or more interiorpanels. The interior panels can be chromogenic and the exterior of acolor which matches with other glazing color. The interior panels couldbe flat and the outer one can be curved. The transmissivity of eachinterior panel can be independently controlled, as for example, by thedriver and the passenger. However, it is not necessary to have twodifferent chromogenic, e.g., EC panels to provide this functionality.Control over several independent sections of a chromogenic panel can beprovided in one monolithic device, as shown in the illustrativeembodiment of FIG. 2B. To fabricate a device having two independentlycontrollable EC sections, the transparent conductive coating 17 may beremoved from upper substrate 10 and the coating 27 removed from lowersubstrate 20 by etching along a line 25 as shown in FIGS. 2B and 2C soas to divide the conductive coatings into separate parts on eachsubstrate. The width of the etched line can be from 0.01 mm to severalmm. Busbars 21, 22 are then deposited on each of the sections as shown.

[0076]FIG. 5a shows an exemplary application of this concept. Forclarity only one substrate 101 is shown with the transparent conductor(shaded areas) 102 and the busbars 103 and 104. For those EC deviceswhere two substrates are used, typically, the second substrate will havea mirror image pattern. In this figure the transparent conductivecoating is etched at demarcation line 105 dividing the windshield in twosections, where both of these can be independently controlled. The toppart 106 when colored would resemble a shade-band concept. In the bottompart 107 one rectangular busbar 104 is shown which is extended on itstwo edges so that connections for power can be made. It is not necessaryto have two extensions; there can be one or more depending on thewindshield size and the voltage (resistive) drop. In the top section 106two busbars 103 are shown which are extended to one side and connected.Just like the bottom one 104, this busbar could be rectangular and thenextended on one side for connection. Since the aspect ratio(length/width) is typically larger than 5, one may not have the sidebusbars without too much noticeable impact on the device kinetics. Theremay even be more horizontal sections, each of which could be coloreddepending on the angle of the Sun (glare source) with respect to thedriver's vision. FIG. 5b shows where the shade band or top part 106 isalso vertically divided at demarcation lines 108 in three parts. Thismay be divided in as many parts as needed; a number of three was chosento demonstrate the concept. The busbars are extended on to the sides inthe non-conductive area 105 so they do not interact with one another.Also the top busbars 103 may optionally be extended (not shown) on oneside by etching a strip of transparent conductor from the top so thatall connections can be made from one side of the glass. For those ECdevices which are fabricated using one substrate and in which all otherlayers including the final transparent conducting layer are sequentiallydeposited one on top of the other, it may be possible that such divisivepatterns are only required on the bottom substrate, or alternatively thetop substrate may use tapes or busbars taking care that they do notshort through the thin layers underneath. The advantage of this designis that mechanical visors could be eliminated and save cost withoutadding significant cost during the EC fabrication process. The EC visorconcept described above may be extended to any of the other car or othervehicle windows.

[0077] These sections can be colored (automatically) or by the userdepending on the glare source position. Automatic control can be via asensor (such as a camera based on a Charge coupled device (CCD) or aComplimentary Metal Oxide (CMOS) sensor) located in the interior of thevehicle, which translates the image into a relative position between theglare source and the driver vision. The camera feedback may also beadjustable by the user (trained by the user) so that it accuratelycolors the section of the windshield which produces glare, relative tothe driver's position. The camera may be mounted or integrated with therear view mirror, but forward looking through the windshield, in the carheader, or on top of instrument panel, etc. For a manual system, thecontrol can be via a push button switch, toggle switch (like an outsidemirror position control), or via touching that part of the glass thatthe user wants to color). Also the user control of the tint for entirewindshield (and/or the bottom part of the windshield if it has a shadeband as described above) or the other windows can be disabled at night,particularly when the ignition is on or if the car is moving, so thatsafety is not compromised. The night senor could be a photodiode,photo-resistor, etc., similar to the ones used in the EC mirror, or onecould make use of the night sensor in the EC mirror. More on EC mirrorsensors and controls can be found in U.S. Pat. No. 5,424,898. Anotherway to offer glare control is to make use of a positioning system in thecar, such as a magneto-restrictive directional sensor (electroniccompass) or a global positioning system (GPS). This coupled with orwithout the above sensors could control the tint of the glazingautomatically. Further, controls can be coupled with occupant sensordevices (typically used for safety bag deployment), so that the comfortfor other occupants can be maximized automatically. The technologydescribed here allows occupant comfort and extended benefits byselective area tinting which was not possible before. Since EC and otherchromogenic technologies allow for gray scale control, the level of thetint can also be varied. Particularly, EC devices can be made whichbleach on removal of power, or by shorting the terminals, thus they canalso be designed so that a user can manually default the system to ableached condition in case of malfunction so safety is not compromised.The control system could link the power supply of various windows viawireless means to the central control system. Such wireless means coulduse standard optical and/or radio frequency technology and/or blue toothtechnology. To ensure that in the event of power failure a safetycommand (such as bleaching of all windows) can be issued, one mayback-up such control system and receivers with emergency battery packs,which may be a rechargeable type. In routine maintenance such packs maybe replaced if their performance drops. In the parked state the windowtint may also be activated remotely by the user by using a differentbutton on the key-fob, or it may be tied to the lock mechanism, so thatwhen the user activates the locks, the windows tint to a darker shadeblocking the view from the outside, and this is reversed when thekey-fob is used to unlock the car.

[0078] The wireless connectivity described above for the chromogenicwindow system using either one of a user interface or central controlsystem can also be used for architectural and mass transportationsystems. When such windows are powered by solar cells which are locatedin close proximity to each of the windows being powered then theinstallation or retrofit of such chromogenic windows is possible withoutany wiring.

[0079]FIG. 6 shows another novel concept of this invention where anelectrochromic shade band is provided which may be gradually fadedtowards the bottom. The concept of an electrochromic shade band ismentioned in U.S. patent application Ser. No. 09/347,807, but thatapplication does not describe an embodiment where power is applied to aset of busbars while the resistance is controlled on another set ofbusbars which are located on the same device. FIG. 6 only shows the twosubstrates 100 and 111 with the busbars 112-119. For a complete ECdevice these will be further coated and then assembled with anelectrolyte in between as described, for example, herein. Also, noindependently controlled sections are shown in FIG. 6, however, itshould be understood they can be accommodated based on the principlesdiscussed above. Also, none of the busbars 112-119 are connected to oneanother, and all have separate connections 120-127 to a junction box128. In a normal EC device the preferred way to power the device will beto connect A, B and E together (connections 123; 124, 127 and 126), andthen C, D and F together (connections 120, 122, 121 and 123) and thenpower the device. This will have the same effect as if all the busbarson a substrate are connected. However, if it is desired to have a bandthat is deeply tinted on the top and gradually fades as it moves towardsthe bottom of the device, a preferred way will be to only apply thepower between B and C (connections 124 and 120, respectively, andbusbars 116 and 112, respectively). If the device has a natural currentleakage one will observe a strong band at the top that fades towards thebottom. For automobiles it is desired to have devices that have low orno leakage so that power is not consumed when these devices are kept inthe colored state for a long time without applying the power. To dothis, while EC power is applied between B and C, the connections A and Dare connected via an electrical resistor. If this resistor is high(higher than 1 mega-ohm), the device will color slowly and will be quiteuniform throughout. If this resistor is low, e.g., less than an ohm, thecurrent leak will be high and very little coloration may be observed atthe top. However, by varying the resistor in between, the leakagecurrent, and thus the band shade size can be controlled. A furthertuning will be required by EC voltage between B and C to get theappropriate color depth. These connections and the resistance selectioncan be automatically provided (at the user's command) by the junctionbox 128 through mechanical and solid state relays and rheostats. Theonly time a shade band will be required is when the car is running andthe user only wants to color the top region, thus in this situation thepower leakage will not be a concern. In the parked state either an opencircuit or high resistance between A and D will be automaticallyselected. Thus the user can select whether a shade band is required oruniform coloration is required, in which case all busbars will beconnected together as explained above.

[0080]FIG. 7 shows a control panel 130, which uses a rotary knob 131 andseveral push-buttons 132 to control the tint of EC glazing. In thisexample it is assumed that all glazing (windshield, the two frontwindows, the two rear windows and the back-lite) including a sunroof areelectrochromic. In the “Auto” mode, the glare by photosensors or abovedescribed systems and/or comfort, e.g., measured by inside cabin oroccupant temperature is automatically determined and the tint iscontrolled accordingly. In the “Manual” mode window tint is selectedfrom bleach, to light tint to dark tint. When the “All windows”push-button is pressed, all windows color according to the knobselection described above. When “Front” is selected then only the frontwindows color as selected by the knob selection above, but the rearcontrol is through another knob (with similar choices) located in therear of the vehicle by the occupants seated there. Further, one mayconfigure the panel in FIG. 7 differently, where instead of “Rear” itsays “Individual”, and then knobs are provided for all the other windowsso that an individual sitting next to that window can exercise control.Further, each window may have several sections and may even be heated.Thus it can be seen that there are hundreds of ways in which the controlpanel and details can be configured, the purpose of this illustration isonly to show that a car or any other vehicle which has EC glazing, canbe provided with customized window tinting or other functions on demand.Since, for most types of chromogenic glazing transmission change is notinstantaneous, a blinking light 133 can be provided as shown on theabove panel, which is turned-off or turned on when a steady state isreached, which could be measured optically by the optical sensorsdescribed above or the current consumed by the EC system till it reachesa steady state or drops below a certain value, e.g., below 1 mA/sqft ofarea. This may be coupled or substituted by audible indicators. A safetymode can be incorporated in the system, where in case of an accident, orlow battery the windows are automatically shorted. For an accidentdetection either a separate shock sensor can be used or it can be tiedto air-bag deployment sensors. In case of a car entering a tunnel orwhen the sensors (described above) detect that it is dark, the frontwindows and the windshield (if electrochromic) would bleachautomatically by applying the bleach power protocol.

[0081] To enhance safety, the rear window may start bleaching when thereverse gear of the vehicle is engaged. If stop lights CHMSL (centerhigh mounted stop light) are mounted inside of a vehicle, one mayinactivate the area through which it illuminates. This can be done byremoving the EC coating (or not depositing the coating) in this area, oretching a fine line in the transparent conductor which is not connectedto powering busbars. Another example of such an application isillustrated in FIG. 8, where a front side window 140 of a car is shown.Since, this window is also used to view the outside mirror, the windowis partitioned along demarcation line 141 so that the driver is able toview the mirror 142 even when the rest of the window 143 is tinted. Thispattern may be optionally repeated on both sides (left and the rightside). The mirror part of the window 144 can be controlled separatelyfrom the rest of the window. Since, this is a smaller section of thewindow this will also color and bleach fast for electrochromic systems.Since, this has a separate control, one could design the electronics inthis part so that it does not color too deeply for safety reasons. Againthis part can be bleached and not user controllable at night asdescribed above. One may even design the window so that this part isalways clear typically more than 70% photopic transmission and its tintcannot be varied.

[0082] In another embodiment the look through area for the mirror 144,can work like an EC mirror at night, i.e., this section of the window isdarkened rather than the mirror, or both may be darkened to increase thecontrast if so desired. This feature can provide the electrochromicmirror functionality without the use of an EC mirror. Since this area inthe window is small, only a deletion line in the transparent conductormay be required without the busbars being present in the vision area forany of the sections. This will keep the visible distractions to aminimum as well. The speed of transition of the area through which themirror is viewed will have to be as fast as an EC mirror, or at leastacceptable for the purpose. For those cars where the mirror is replacedby an internal screen or the image is collected and displayed inside inthis corner (but inside of the vehicle), one may still use thepartitioning described above so as to shade the display from glare, evenif the rest of the window is in the bleached state. Either the entirewindow or only this section may be configured with a heater (asdescribed below) for defrosting.

[0083] This and other car windows can also be divided in sections asdescribed above so as to control specific areas for glare while leavingthe other areas clear. Examples may be to enhance the contrast if aHeads-up-display is used which is typically located in the windshieldarea. The partition between the driver and the passenger compartment ofa bus, boat, limousine may be divided by an EC panel, which may haveseparately addressable panels depending on the need. One may evenintegrate displays as a section of the EC panel. The pixels of these canbe individually addressed as described in an earlier example where theshade-band was divided in three parts. The display can be driven usingstandard interface to display information on fare, approaching towns,sights, time (clock functions), etc. For those windows that open, onecould have the EC action (power) be cut-off or bleached when the windowis rolled from its completely closed position, or if it is only openedbeyond a certain measure. However, for windows that move, it isimportant to provide a cable management so that the wires do not getentangled, linear springs or rotation devices to ensure that the wiresdo not have excessive slack, but also give in easily when they need tobe extended.

[0084] For the glass in the rear of the automobile (or the back-lite),one typically finds the heater bars for defrosting. The position ofthese can be matched with that of the busbars for the chromogenic deviceso that the visibility through this is not affected. Further, some ofthese busbar locations could be partitions so that only selective areascould be colored if so desired. The heating strips could be substitutedby wires, which run through the electrolyte. However, care has to betaken that an inert, non-porous coating, which does not react with theelectrolyte or any of the components in the cell, and at the same timedoes not block the thermal transfer to an appreciable extent, passivatesthese wires. Typically these wires should not be heated above 100° C.preferably above 75° C.

[0085] Another novel way to heat electrochromic panels is the use of thetransparent conductor as a heater and as the electrical path to powerthe EC device. Although this general concept is described in U.S. patentapplication Ser. No. 09/347,807, the disclosure is directed to how thevoltages to the two opposing conductors in the EC device are controlleddifferentially. This is difficult to implement practically, as thevoltage inside the cell changes with coloration.

[0086] A practical implementation of this concept is shown in FIG. 9.Again, for the sake of clarity in demonstrating the concept only onesubstrate 150 is shown and no sections are shown. The busbars 151-154are shown all around the substrate, but they are not connected with eachother (although they may be electrically connected by the underlyingtransparent conductor) and also, they have independent connections155-158. All the connectors are routed through a junction box 159 withmechanical or solid state relays. When such a system is used where theEC device function is needed, the connectors 155-158 are all furtherconnected to the EC power source together through this junction box. Thesecond substrate (not shown) or the electrode may have the same patternof busbars, if a junction box is used, or a continuous busbar with noseparate sections. The power is applied to color or bleach the cell,which is device dependent, but typically less than ±3V. However, if onewants to use this device as a heater, the junction box routes the topconnection 158 and the bottom connection 156 to two separate terminalswhere a higher voltage is applied, typically 12 to 42 volts and the maxcurrent for a typical rear-lite is less than 5A, preferably lower than3A. Preferably, the side busbars 153 and 154 are not powered forheating. To use both the EC and the heating mode, one could timeproportion between the two functions via the junction box, or one mayapply an EC voltage to the second substrate in relation to the first sothat the potential difference does not exceed the safe EC potential forthat device. This concept is usable not only for backlites but allwindows without interrupting the vision. The temperature of the heatershould be typically controlled below 100° C., more preferably below 75°C. and most preferably below 50° C. The internal busbars may evenfunction as antennas, or during processing the conductors for antennasare deposited while depositing the busbars for the EC device, preferablyof the same materials to save cost.

[0087] As an example FIG. 10 shows a side view of an EC device, where A,B, C and D correspond to the four connections labeled similarly in FIG.9. Connection E is from the other electrode, where only one busbar isused all around. This figure shows the substrates (S) 160 and 161,transparent conductors (TC) 162 and 163, electrochromic layer (EC) 164,counterelectrode layer (CE) 165 and the electrolyte (E) 166. FIG. 11shows an exemplary circuit diagram to power the EC window in a bothheater mode and the EC mode. This shows that a micro-controller 170controls the switches to the EC power supply, the heater power supplyand the switch positions. It also has an optional temperature sensor(thermistor, thermocouple, etc.), which monitors the device temperature.This could be located (and bonded) to the outside of the glass aboutmidway between the top and the bottom busbars. It is preferably locatedclose to the edge so that it can be hidden by the frit or the edgeencapsulation. Its output can be corrected for the thermal lag both interms of time and magnitude. Alternatively, one may not require atemperature sensor or its measurement, if desired the temperature may beestimated as given below. The temperature may be estimated by theelectrical resistance when EC color or bleach voltage is applied. Theresistance will depend on the temperature, type of device and the areaof the device. For EC devices with a counter-electrode configurationdescribed in the examples later, this can be in the vicinity of 100ohms/ft². When a high resistance is detected the heating circuit isapplied for a duration so that the window becomes reasonably warm (15 to50° C.) before the EC circuit is applied. The micro-controller ensuresthat at any given time either the heating or the EC power supply are onand that they are not shorted. Depending on the algorithm itautomatically turns one off and the other on. Current consumed by the ECdevice can be taken as an indication on when to turn the power off tothe cell during the coloration and bleach. When the EC power supply isconnected to the cell, switches 20 and 18 are closed. In this positionswitch 20 is connected to E and A, B, C and D are connected to switch18. Also the switches 1,4,7 and 10 are in contact with 2,5,8,11respectively so that A, B, C and D are connected. When the heater powersupply is providing the heating power, switches 19 and 17 are open, andswitches 16 and 14 are closed. Also the switches 1, 4, 7 and 10 are incontact with 3, 6, 9, 12 respectively so that heating power is onlyapplied to B and C. All these are controlled by the microcontroller andthe switches are mechanical or solid state relays (SSR). Examples ofthese and details on EC power supplies can be found in U.S. patentapplication Ser. No. 09/347,807, the disclosure of which is incorporatedby reference herein. Some other substitutes for relays are MOSFETs(metal oxide semiconductor field effect devices), JFETs (Junction fieldeffect devices) and bipolar transistors. These and micro-controller arestandard electronic components which people in the art are familiarwith.

[0088] The chromogenic technology (materials and processing) will changewith time. This may cause the new panels to require different poweringrequirements or their tint may be lighter or darker. Given this it isimportant to incorporate features if one of the several windows may haveto be changed in a system (e.g., a car, a bus, etc.). One way is toequip every window with a memory module such as an EPROM (erasableprogrammable read only memory), SRAM (Static random access memory), FRAM(Ferroelectric random access memory), Flash RAM or a similar module,which contains the information about the driving requirements of theglass. This module is interrogated by the control system before power isapplied. The stored data can be voltage/current/time characteristics,change of these with temperature, temperature limits for operation,aging characteristics and corrective actions, how to access differentpartitions if any, preferred control and feedback mechanisms, etc. Thismodule can be a part of the harness, which powers the glass or could beeven bonded on to the glass. Another way could be to provide aninterface between the main controller and the powering leads to theglass, which has this information. The controller may also measure theintrinsic properties of the glass, such as its electricalcharacteristics (e.g., resistance) and then decide how to power themodule. The camera sensor described above, or a photo-sensor may be usedto provide the feedback so that the windows are colored to about thesame extent. This information may also be built into the memory moduledescribed above where charge consumption vs. optical density may also belocated.

[0089] For automobiles where all windows including the sunroof arechromogenic, it may be difficult to locate wireless receiving devicessuch as global positioning systems (GPS), cellular equipment, etc.inside the passenger compartment as the transparent conductors in suchdevices may block or attenuate communication signals. This isparticularly applicable for those automobiles where all the body panelsare constructed from metals. The chromogenic windows described in FIGS.5a and 5 b can accommodate this need because such signals can passthrough those areas in the glass where the transparent conductor isremoved. Some of these areas may also be located close to the glassedges which are typically covered by dark frits and paints. Another wayto overcome this problem is to have external antennas which are linkedwith the interior cabin via hard wires, and which may be further linkedby hard wires or wirelessly with other interior devices. Another novelway to overcome this problem could be the incorporation of opticaldevices so that the communication from inside to the outside thepassenger compartment (and vice-versa) can take place through thetransparent windows. These optical devices 109 would be preferablylocated in those areas from where the transparent conductor is removed,such as illustrated in FIG. 5a. These areas can also be used to locateother optical sensors. The preferred sensors would communicate in theInfra-red, and more preferably in the wavelength region of 800 to 1800nm. The optical devices or wave-guides to carry the signal from or tothe edge of the glass may be etched or embedded in the glass laminates.

[0090] Another problem which may be encountered is where chromogenicglazing is used in large expanses, particularly in buildings and invarious transportation, particularly mass transportation. When largefacades are made up of chromogenic glazing, and all of them do notdarken to the same extent, particularly with aging, then it can give achecker board effect. This may reduce the cosmetic attraction. Withaging the efficiency of the chromogenic materials may change, and someof the windows may be replaced by new ones due to breakage, etc. Theresulting non-uniformity of appearance could happen to the viewers fromthe outside or the inside occupants who are in rooms where a number ofsuch panels may make-up a wall or a large area. A way to mitigate such aappearance is to use imaging sensors, such as cameras, and a preferredsolution are inexpensive CMOS (complimentary metal oxide semiconductor)cameras. It is further preferred to use digital cameras to provideeasier communication and eliminating the need for data conversions fromone format to the other.

[0091] Use of cameras as an optical sensor is described in U.S. Pat. No.6,039,390. However, the use of such optical sensors to overcomepotential non-uniformity of large area glazings is not described. Thesecameras can be located on the outside of the building and/or in theinside of the room. This concept is illustrated in FIG. 14 which showsthree walls, 200, 201 and 202 of a room. A sensor 203 is located on wall200 opposite wall 202 which is comprised of a plurality of chromogenicglazings 204. Where such a sensor 203 is located in a room, on, a wallwhich is facing the chromogenic glass wall/window, the sensor 203 willperiodically take the image of the window, and send a signal to theindividual sections of the chromogenic panels 204 which are controlledindependently of one another to change the powering conditions so thatan equalization of the tint can take place. The feedback from the cameracan be used to make adjustments till the tint discrepancies amongst thewindows are removed. The image processing algorithms can take account ofimage distortions caused by shadows, which typically would cause theimage to be darker in certain areas for the same chromogenic panel, andthe shapes may not follow the geometric demarcation of the individualpanels. Further, if shadowing glare is being caused by specific panels,then that may be programmed in the system, or indicated by the user sothat the tint equalization may be different for one set of panels ascompared to the other set of panels. Further, image sensors may be usedto distinguish permanent obstructions, versus the changes due to thelight intensity caused by the modulation of light by the chromogenicwindows. If needed such cameras may be also tied to other functions suchas surveillance. The control system may even provide a choice to thebuilding occupants to over-ride the automatic system of equalization, sothat they can use their own tint pattern or to control glare on aparticular spot in a room, such as on their computer monitors. Anotherexample may be preferentially coloring certain windows 210 of a buildingto display a sign, such as a corporate logo. An example of this is shownin FIG. 15 which illustrates a window 210 comprised of a plurality ofchromogenic panels 212. Each pixel 211 in the logo can be onechromogenic window element which is independently controllable orseveral of these.

[0092]FIG. 16 shows a block diagram where a plurality of image sensorsystems 222 are tied to a central energy management (includinglighting)/building management system 220 and to the individualcontrollers/power supplies 221 for the chromogenic windows. FIG. 16illustrates individual power supplies/controller 202 for threechromogenic window facades corresponding to each image sensor 222. Theseconnections can be hard wired or wireless or mixed. FIG. 16 is only anillustration of one possible configuration. In another configuration,the image sensors may be directly linked to the powersupply/controllers. The wireless devices may be products using BlueTooth hardware and protocols. The communication may use internetprotocols, as such communication media are generally available in mostareas of the building. Some examples of central management systems areTABS™ by Netmedia Inc of Tucson, Ariz., Integrated BuildingEnvironmental Communications System (IBECS) from Lawrence Berkeleylaboratory (Berkeley, Calif.). There may be external sensors (mountedremote from the building such as another building, a pole in the parkinglot, etc.) which are used to control the tint inequality. Also theexternal and internal image sensors, i.e., more than one image sensormay be used to control a chromogenic facade. An electrochromic windowcontrol system is described in WO 00/10770, which could be incorporatedin the inventive system described above which uses image sensors.

[0093] As mentioned above, the busbars used in the devices of thisinvention can be silver frits, but conductive tapes or soldered linesmay alternatively be used. One substrate is then coated with e.g.,tungsten oxide or doped tungsten oxide and the other with acounterelectrode. Examples of counterelectrodes are vanadium oxide dopedvanadium oxide mixed with oxides of cerium, titanium, niobium and nickeland manganese oxide based systems described above. The cell is assembledwith these two substrates facing inwards with the electrolyte inbetween. Since, electronically the two sections are not connectedtogether one could only power one section and not the other.

[0094]FIGS. 2, 3, and 4 show that a transparent conductive layer 15, 21or 45, 35 has been etched, preferably on both substrates 10 and 20,respectively. If different chromogenic sections have to be controlledindependently to a different transmission or color, then it may bepreferred to etch both.

[0095] The partitioning mechanisms of FIG. 2C, 3B or 4 may thusadvantageously be used to section car sunroofs where each section isindependently controllable. Similarly, an electrochromic windshield maybe effected that has a sunshade band at the top which could be adifferent section from the rest, and even have different chromogenicproperties, as described above while the remainder of the windshieldneed not be chromogenic; meaning either that the EC layer or theconductive layer underneath may have be removed or not deposited.Alternatively, one may use a substrate which is only as big as therequired visor and which is then fabricated in to a device by laminatingonto a larger substrate such as the entire windshield. Another examplecan be a chromogenic cover for the instrument panel for the car. Thisinstrument panel can have different sections and the transmission ofeach section could be independently controlled to provide the desiredfunctionality or to maintain the most desirable vision/least glare froma driver's perspective. Since EC technology has variable control, thedifferent sections can be controlled to different depths oftransmission. For instrument panels, it is preferred that the EC deviceshave a-photopic range of more than 70% down to less than 20%. Furtherantireflective coatings (average visible light reflection less than 1%)on these panels will keep the visual interference from reflected lightlow. The car windows can also be sectioned to maximize the passengerand/or driver comfort.

[0096] EC Device Processing

[0097] As mentioned, chromogenic panels may be flat or curved, e.g., fora car glazing such as a sunroof. To make a chromogenic device such as anEC device for a sunroof, the preferred methods are disclosed below. Thismethod preferably employs two substrates, but those with one substratewith all thin film construction can use the same method as well. Forexample, the outer substrate for the sunroof can be a dark glass with athickness of 2.5 to 6 mm, preferably 2.8 to 4.5 mm, GL20, GL35 orOptibronze™ (all from PPG, Pittsburgh, Pa.) are typically 4 mm thick.The outer glass should be of a thickness capable of being strengthenedor tempered. For this to be done by thermal treatment typically requiresa thickness of about 2.5 mm or more. However, as the thickness increasesthe weight increases. The max strength to weight ratio is achieved witha thickness in the range of about 3 to 4 mm. An alternative is to usethinner strengthened sheets that have been strengthened by a chemicalprocess where compressive stresses on the surface are introduced byexchanging the smaller ions with the larger ones. For example,exchanging of Na+ ions with K+ ions. If those glasses are used whichconsist of lithium ions then they can be replaced with sodium ions.Chemical strengthening, especially for drawn glass also results inpreservation of shape, particularly useful for bent glass. Preferredphotopic transmission lies in the range of 20 to 80%. The preferredphotopic transmission of the outer glass is lower than 50%. Thistransmission is measured with the conductive coating but without an ECor a counter-electrode coating. Flat sheets of this glass can bepatterned with the silver busbar frit. The glass is then bent andtempered (or strengthened) while also curing the silver fit, all in oneprocess, (the bending of the outer piece of glass for the EC deviceshould have the silver frit on the concave side). A dark non-conductivefrit may also be applied to the glass along with the silver frit as longas the silver frit is not masked. The silver frit may also be depositedon top of the dark non-conductive frit. A transparent conductive coatingsuch as indium tin oxide (ITO) is deposited on the substrate so that itcontacts the silver frit. The ITO processing preferably takes place ator below 400° C. During bending and strengthening, the frit is heattreated to the final state, but the atmosphere (such as oxidizing and/orreducing (either one of these or in a sequence of any one of thesefollowed by the next one)) could also be controlled so that the ITOconductivity increases and its transparency increases by optimizing itsstoichiometry (cation to oxygen ratio in the oxide coating) and thecrystal grain size. The second substrate could be similarly processedand be tinted or clear. The frit area may only be subjected to localizedheating which follows the frit path. The heating source can be a laser,induction heating or a focused IR or visible light lamp. Preferredphotopic transmission of the inner glass is greater than 60%. Thistransmission is measured with the conductive coating but without an ECor a counter-electrode coating. However for this case the frit andconductive coating will be on the convex side of the curvature. One mayeven deposit ITO before the frit deposition and bending andstrengthening operation. Since it is desirable that the curvatures ofthe two substrates be matched, it is preferred that both of thesubstrates be bent together as a pair or bent separately using a mold.

[0098] The second substrate (inner glass) in the above case could besimilar in thickness to the outer glass, but preferably is thinner, inthe range of 0.8 to 3 mm to keep the weight low. One may even use theconventional TEC glass (from Pilkington LOF, Toledo, Ohio), TCO glassfrom AFG (Kingsport, Tenn.) or Sungate 500 from PPG (Pittsburgh, Pa.)which has a fluorine doped tin oxide coating on one side of the glass.This glass can be clear or colored, where the color could be introducedfrom coatings or layers below the conductive layer (an example beingSolar E glass from Pilkington LOF). The color of this glass could bedifferent or have a different coloration depth as compared to the outerglass. Preferred photopic transmission of this glass is in the range of20 to 90%. If this glass is thin, this may not be amenable for thermaltempering or strengthening to the same extent as the thick glass.However when the outer and the inner glass are laminated together toform the EC device, the composite could still meet all the automotivesafety requirements from a crash simulation or an equivalent test (e.g.,Society of Automotive Engineer's test Z26.1-1990). To meet the safetyregulation one may use both glasses that are thin and unstrengthened,and still pass this test depending on the mechanical properties of theelectrolyte film. Another way to meet the test requirements withoutstrengthening the inner panels is by laminating them with plasticlaminates such as Spallshield™ and Sentryglass™ by Dupont (Wilmington,Del.). Several Fluorine doped tin oxide coated glasses keep theirconductivity even after bending and strengthening operations.

[0099] The substrates are then coated, e.g., one side with tungstenoxide and the other side with a counter-electrode and then eitherlaminated with a electrolyte film and edge sealed to prevent ingress ofmoisture and other atmospheric elements, or made into the EC device byedge sealing to form a cavity and then filling this cavity with theelectrolyte (e.g., a method for this is given in U.S. Pat. No.5,856,211, which is incorporated herein by reference). Further, if thecounter-electrode is such which may require a high temperature treatmenttypically greater than 400° C., one might consider depositing thisbefore the glass is bent and/or thermally strengthened, so that the sameheat treatment could be used to heat treat this coating as well. On oneof the substrates the conductive coating may be deposited first beforethe frit was deposited, and on the other substrate, the frit may bedeposited first, followed by the transparent conductor.

[0100] The principles of these constructions and the way to processdevices with bent or flat glass can also be used for those devices whereno active EC or other chromogenic coatings are required. These devicesuse liquid crystals, suspended particles or EC devices which use atleast two redox species in the electrolyte. UV protection can beprovided by incorporating additives known in the art to the electrolyte,glass substrates and/or coatings which are deposited on them (which maybe on surfaces external to the device and even further laminating themwith materials which provide the UV barrier). Many of these areexplained in the references cited and for example in U.S. Pat. No.5,864,419 (which is incorporated herein by reference).

[0101] The principals of EC device construction are not limited toautomotive and other transportation glazing, but any application whichwill benefit from this invention, including architectural glazing,decorative chromogenic tiles, lamp covers, displays, mirrors,appliances, cabinets, etc.

[0102] Composite laminates can be made using chromogenic glass wheresuch elements are laminated with other elements to give addedfunctionalities. For example, the additional elements can have heaterpatterns/elements, antenna patterns/elements, alarm patterns/elements,bullet proof elements/layers, etc. The heater filaments may be so finethat they are scarcely seen by the naked eye. The alarm elements mayactivate an alarm when the glass breaks. Examples of suchlaminates/elements without chromogenic elements are available under thetrade name of Swisslamex® from Glastrosch (Butzburg, Switzerland). Tomake these novel composites, one of the laminating substrate is thechromogenic cell. On the surface of the cell the above describedelements are deposited and then laminated with an additional substrate.Alternatively, one may deposit these elements on the additionalsubstrate before laminating them with the chromogenic member. For analarm, typically a conductive line pattern is deposited which is thenincorporated in the laminate. When the glass breaks the electricalcontinuity is disrupted which is then sensed by a connected circuit. Inthe case of heater, conductive coatings, wires or conductive fritpatterns are deposited which heat up when electric current is passedthrough them. They may have thermocouples, positive thermal coefficientelements, etc., attached to them to limit the maximum temperature.Similarly, for antennas, conductive patterns or wires are used which arethen connected to an appropriate circuitry. For bullet proofing severalglass and/or plastic sheets need to be laminated so that the energy fromthe bullet is absorbed by breaking the numerous layers and bonds betweenthe interfaces. Thus, novel composites can be made by combining elementsdescribed above with chromogenic panels.

[0103] Powering of Chromogenic Devices

[0104] The power to chromogenic devices, such as a sunroof, can bedelivered in several ways. The power supply to the chromogenic panel canbe optionally integrated as one unit with the power supply that is usedfor powering other functions of the sunroof such as sliding and tilting.Further the power supply may even be optionally integrated to providepower to even other car functions e.g., to power the header console orthe car interior, including electrochromic mirrors, lights, displays,communication (within internal car functions and external functions suchas remote keyless entry or radio and microwaves), and locks. Differentfunctions require different power characteristics (such as voltage,alternating current or direct current), thus they need to beappropriately shielded to reduce interference. Amongst other benefitscombining several functions in one power supply will reduce the currentdrain on the car and cost.

[0105] Power supplies for the electrochromic devices are extensivelydescribed in patent application Ser. No. 09/347,807. Electrochromicdevices which have a intercalatable counterelectrode and an EC electrode(such as tungsten oxide including doped tungsten oxide) separated by anelectrolyte layer can be powered as discussed below: the electronicswill be capable of powering preferably in a range of +2V to −2V. Theapplied voltage will be dependent on the amount of coloration requiredin the EC cell. The cells can be powered by a constant current(preferably, lower than 1 A/sq.ft of EC area, more preferably 0.5A/sq.ft of EC area) but limited by a max. voltage (within the preferredrange of +/−2V). The maximum voltage and the maximum current may dependon the cell temperature (thus an input for cell temperature will berequired). The voltage will be lower at higher temperatures.

[0106] To keep the power consumption low it is preferred to useswitching power supplies to step down all or part of the potential fromthe battery to the applied potential. One may use the switching powersupply to step down the potential to say 3V or 5V, and then use thelinear regulation to tune it to the specific potential. Switching powersupplies are those that use a DC to AC conversion and then back to DC toconserve power. This conversion is done by capacitive or inductivecoupling. This becomes more important if the main battery voltage ishigher. Typical output of DC batteries used in transportation range from42 to 12 volts. Between the input and the output voltages the conversionefficiency of switching power supplies is greater than 50, and mosttimes greater than 70%. Some sources of such power supplies are MaximIntegrated Products, Inc. (Sunnyvale, Calif.), Linear TechnologyCorporation (Milpitas, Calif.). These high efficiency switchingregulators using inductors or capacitors are sold under many genericnames, some of these are: high efficiency switching regulator; highefficiency switching regulator; high efficiency switching voltageregulator; high-efficiency pwm step-down converter; high-efficiency pwmstep-down controller; micropower 600 khz pwm dc/dc converter; step-downswitching regulator; high efficiency, synchronous step-down switchingregulators; high-efficiency step-up converter; wide input range, highefficiency, step-down switching regulator; high efficiency in switchingregulator using capacitor; switched capacitor voltage converter;switched-capacitor wide input range voltage converter; micropower,regulated 5 v charge pump dc/dc converter; high efficiency inductorlessstep-down dc/dc converter; switched capacitor regulated voltageregulator; 5v regulated charge pump; step-up/step-down switchedcapacitor dc/dc converter. Some of these from Linear Technology aredesignated LT1026, LT1054, LTC1144, LTC1503-1.8/LTC1503-2, LTC1515,LTC1516, TC1550/LTC1551LLT1070/LT1071, LT1074/LT1076,LT1170/LT1171/LT1172, LT307/LT1307B, LTC 1929. Some of these from Maximare designated MAX887H, MAX682/3/4MAX738A, MAX758A, MAX1684, MAX1715,and MAX1636. One may even use the commercial battery charger integratedchips as the heart of the power supplies. Although, the output voltageof these will have to be further regulated to be in the desired range.Some examples of these are DS2760 from Dallas Semiconductor (Dallas,Tex.), MAX1645 and MAX1645A from Maxim. these already have built-inswitchable power supplies within the integrated chip.

[0107] For many chromogenic devices the coloring and bleaching power(voltage-current-time) is temperature dependent. One could measure thetemperature of the device by measuring the temperature on the surface orthe interior (such as the electrolyte) of the device. However, for mostchromogenic devices it may be sufficient to know if the temperature ishigh or low. For example, high temperature may be designated as beingabove 40 to 60° C. On automobiles or other vehicles, one could usephotosensors (e.g., those placed in electrochromic mirrors orspecifically placed sensors for glazing) and an outside or inside thevehicle temperature sensor to determine if the chromogenic environmentis hot-or cold. As an example, if the photosensor senses that it is daylight and the outside ambient temperature is greater than 35° C. (asmeasured by an outside the vehicle temperature sensor) then one may usethe chromogenic power condition for high temperature. Another example,would be where the photosensor senses it is day light and the interiorcabin of the vehicle temperature is greater than 50° C. (as measured byan interior vehicle temperature sensor) one could trigger the highertemperature powering condition. This concept could also be used inbuildings. For example, the temperature between the space created by anintegrated glass unit (IGU) in which one of the panels is chromogeniccould be measured.

[0108] Glazing for Boats

[0109] The above constructions can be used to make glazing for theboats. This invention is particularly suitable to make glazing forcabins and the bridge (navigation room) of the boats. The boats need tobe navigated both during the day and at night. When tinted glazing isused for this, so that the people in the room can be protected fromharsh Solar radiation during the day, the same tinted glazing causespoor visibility in the late evenings and night. Thus use of chromogenicglazing in this application will enhance comfort and safety. Further,the reflection of the sun from water may also result in blinding glare.Since the light reflected from the water is polarized, one could use apolarized sheet, which is incorporated within the chromogenic glazingand further enhance the comfort and safety. The use of polarizer in thedevice which will polarize the light perpendicular to the reflectedlight will result in blocking the specular reflections from the water. A“sandwich” made of a glass substrate, laminating material, polarizinglayer, another laminating layer and a chromogenic element layer, inwhich the glass substrate faces the outside is desirable. In thisconstruction, both the chromogenic element and the polarizer can beprotected by UV radiation from the UV blocking characteristics of thesubstrates and/or the UV blocking characteristics of the laminatingmaterial such as polyvinylbutyral, polyurethane or polyvinylchloride.The laminating materials have UV blocking additives (or stabilizers).Also the other side of the EC element may also be optionally laminatedto block UV entering from the other side. The UV blockingcharacteristics also protect the interior of the boat against aging andfading from the Solar UV radiation. Further, one may provide silver orother busbars on the inside of the glass substrate or the outsidesurface of the EC element for defogging. Another set of busbars couldalso be introduced for antenna of radio and microwave signals. One couldalso coat the outer surface of the glass with hydrophilic coatings forwater to spread out or hydrophobic coatings for water to bead-up so thatgood visibility is maintained even when water droplets hit the surface.One may also coat the outer surface with titania to provide for selfcleaning properties and/or hydrophillicity (e.g., see JP11228865A,JP10277403A and JP10140046A). The preferred transmittance range for aboat glass should be greater than 30% photopic, and more preferablygreater than 60% photopic in the bleached state. In the colored statethe photopic transmission should be less than 25%, and more preferablyless than 10%. The preferred colors are again warm and neutral colors.However, the green and blue colors are also acceptable in this industry.The use of colored and or contoured substrates or cover glasses whichhave the desired colors and design will assist in matching of theexterior appearance.

[0110] Display Filters

[0111] Display filters, especially those that are to be compatible withnight vision systems may profit from the application of the illustrativechromogenic assembly with polarizing materials. For example for militaryuses one may use static filters in front of displays to block out thenear Infrared (NIR). This is done so that in the evening/nighttime whenthe vehicle or airplane operations personnel use night-vision system,they do not get blinded with the NIR being emitted from the displays.These filters should meet the Military Specifications MIL-L-85762-A.According to this specification various color filters are used for theNight Vision Imaging System (NVIS). These are typically NVIS Green A,Green B, Yellow and Red. This standard requires that the displays notexceed NVIS radiance of 1.7×10⁻¹⁰ when lightening produces 0.1 fLdisplay luminance. The warning or master caution signals may bebrighter, at levels between 50 and 1.5×10⁻⁷ with source luminance levelsup to 15 fL for class A Type 1 goggles. NIR for night-vision beingdefined at least the region between 700 and 1100 nm. Typical glasscompositions used for this purpose contain P₂O₅ in their compositions inthe range, of 30 to 60 mole % and copper (ll) oxide (CuO) in less than40 mole %. These are described in U.S. Pat. Nos. 5,234,871 and in5,036,025, which are both incorporated by reference herein. There areother glass forming ingredients in these compositions which aredescribed in the above references. One such phosphate glass is S-8022 (2mm thick glass) and S-8023 (3 mm thick) glass from Schott Glasstechnologies Inc.(Duryea, Pa.) which transmits in green. Glasses thattransmit white light, yellow and red are for example available fromOxley Avionics (Branford, Conn.) or Kopp filters from Bes Optics Inc (W.Warwick, R.I.). Many of these colors are produced by laminating at leastone of the glass substrates which has copper and phosphorous asdescribed above with a substrate which has other desirable spectralcharacteristics. The purpose of this invention is to provide the nightvision capability to the filter and also user controllable opticaltransmission. This can be done if at least one of the substrates in achromogenic device has such glass composition. The schematics ofconstruction of various chromogenic devices are shown in PCT 98/08137.Yet another way to provide this functionality is to take a regular glassand coat this by a composition of material, such as the glass describedabove, and then use these substrates for device building. Coatingmethods such as physical vapor deposition, wet chemical deposition, etc.may be employed. Wet-chemical route is preferred due to the severalcomponents in such coating mixture, thus controlling the homogeneity.

[0112] Display glasses can also be made to deliver high contrast,particularly for the full color displays. These glasses are such thatonly the specific wavelengths at the phosphors emit will be transmitted.These can be further combined with antireflective coatings to givebright displays even in full sunlight. For example phosphor P43 willhave emission bands at 544 and 445 nm and Phosphor P22 will emit at 525and 630 nm. Thus the glass should have high transmission at thesespecific wavelengths. Typically glasses with multiple absorptionscontain rare earth oxides such as neodymium oxide, erbium oxide,ytterbium oxide and mixtures thereof. Typical range of this is between 2and 20% of the glass composition. As above, glass will also containother oxide ingredients to impart other properties, such as silica asnetwork former, additives for UV suppression, enhancement of absorptionin other wavelengths, viscosity modification, durability enhancement.Examples of these are given in U.S. Pat. No. 5,190,896, which isincorporated herein by reference. As described for the night-visionsystem chromogenic display filters, which can change their transmissionwith change in ambient lighting and still maintain high contrast can bemade by using at least one of such substrates in their construction. Forexample a night vision system display filter could be made by combininga said copper containing phosphate based substrate and a said neodymiumbased substrate in a chromogenic device. An example of a night visioncompatible filter that transmits in specific wavelengths for highcontrast is made by Wamco (Fountain Valley, Calif.) called NV-2MC. Someof the glass surfaces may have to be coated with a barrier coating suchas a SiO2 having a thickness range of 10 to 1000 nm. The transparentconductor is then deposited on the barrier coating. The barrier coatingprevents undesirable leaching of cations from the glass and theirsubsequent transport into the conductive and other layers.

EXAMPLE 1 Fabrication of Electrochromic Devices (Devices 1, 2 and 3)With Tungsten Oxide Electrochromic Layer but Without IntercalatingCounterelectrode

[0113] A 3×3 inch (7.6 cm×7.6 cm) EC window device (Device 1) was madeusing TEC 15 (from Pilkington LOF, Toledo, Ohio). The tungsten oxidecoating, a lithium tungstate (Li_(0.3)W)O_(x), was deposited on TEC 15glass. (This is not a reduced form of tungsten oxide as lithium ispresent as an oxide.) The thickness of the fired coating was 360 nm. Thecoating was fired in a humid atmosphere followed by a heat treatment upto 250° C. Details of deposition and precursor used can be found incomparative example 1 of PCT 97/05791. The coating was then etched fromthe perimeter area (about 10 mm in width) of the substrate. A cell wasfabricated by dispensing an epoxy around the perimeter of one of thesubstrates. This epoxy contained 210 micrometer (diameter) sphericalglass beads. The epoxy was dispensed on the etched area. The secondTEC15 substrate was lowered onto this one while providing an offset ofabout 5 mm along one of the edges. This substrate had two 1.6 mmdiameter holes along its diagonal about 10 mm away from these corners.Care was taken that the epoxy touched the tungsten oxide coatedsubstrate in the etched area. The spacers provided a separation of 210micrometers between the two substrates, which would be the thickness ofthe electrolyte. The preferred thickness of the electrolyte is between37 micrometers to about 5 mm. The epoxy was cured at elevatedtemperatures (typically in the range of 80 to 200° C.). Typical curingtime is between 10 minutes to a few hours. Injecting through one of theholes filled the electrolyte. The electrolyte contained (all weight %)0.35% ferrocene, 10.5%LiCF₃SO_(3, 48.9)%PC, 32.6% sulfolane and 7.65% ofpolymethylmethacrylate with a molecular weight of about 540,000. Theholes were then sealed with Teflon plugs followed by glass cover slides,which were bonded by a UV curable adhesive. Alternatively, the plug areamay be sealed with metallic caps, as described in Example 4. To furtherenhance the environmental barrier the edges of the cover slide werecovered with a thermally cured epoxy.

[0114] The same process as described for device 1 was used to makedevice 2, but the tungsten oxide coating solution also includedchromium. The composition of the coating was (Cr_(0.001)Li_(0.3)W)O_(x)The electrolyte was composed of (all compositions are based on weight %)0.8% t-butyl-ferrocene, 0.6%LiCF₃SO₃, 3.7% Ethyl 2cyano 3′-3diphenylacrylate (UV stabilizer), 45.4%PC, 31.7% sulfolane and 8.2% ofpolymethylmethacrylate with a molecular weight of about 540,000.

[0115] Another device (Device 3) was made where the coating wasCr_(0.005)Li_(0.3)W)O_(x). The electrolyte in Device 3 was 1.0%t-butyl-ferrocene, 20%LiCF₃SO₃, 1% Ethyl 2cyano 3′-3 diphenylacrylate,73%PC, and 5% of polymethylmethacrylate with a molecular weight of about540,000.

[0116] The devices were colored by applying 1.2 volts (tungsten oxideelectrode was negative) and bleached at −0.3 volts. The L*C*h andphotopic transmission values of the three devices is shown in Table 1.Also shown in this table are measured values of Cover Glass GL20, GL-35and Optibronze respectively. When the above devices are combined withthese glass covers (all 4 mm thick) by overlaying them on devices, theircomposite L*C*h and photopic transmission values are also shown in thistable. The table also shows how using different cover glasses cancontrol the color perception of the devices. Photopic Color L* C* h (%T) Perception* Bleached EC devices Device 1 88.5 10.5 108.4 73.1 Device2 86.9 16.7 104.6 69.9 Device 3 87.1 17.3 104.3 70.3 Colored EC devicesDevice 1 68.3 13.0 221.0 16.1 Blue Device 2 47.2 21.0 236.9 16.1 BlueDevice 3 50.0 16.9 229.5 18.4 Blue Cover Glasses GL-20 46.7 0.94 243.215.8 Neutral GL-35 65.8 1.6 125.3 35.0 Neutral Optibronze 58.9 23.2 72.826.9 Warm Bleached EC devices with GL-20 Device 1 40.3 5.4 115.0 11.4Neutral Device 2 39.5 8.9 109.1 10.9 Neutral Device 3 39.5 9.1 108.811.0 Neutral Colored EC devices with GL-20 Device 1 24.5 9.6 240.9 2.5Neutral/Blue Device 2 17.4 11.9 244.9 2.4 Neutral/Blue Device 3 19.9 8.9233.4 3.0 Neutral/Blue Bleached EC devices with GL-35 Device 1 57.6 8.9110.8 25.5 Neutral Device 2 56.5 13.2 106.7 24.4 Neutral Device 3 56.613.6 106.4 24.5 Neurontin ®tral Colored EC devices with GL-35 Device 138.1 11.1 230.4 5.4 Neutral/Blue Device 2 27.8 14.4 237.1 5.4Neutral/Blue Device 3 30.4 11.3 226.5 6.4 Neutral/Blue Bleached ECdevices with Optibronze Device 1 51.5 26.1 79.0 19.7 Warm Device 2 50.629.2 80.5 18.9 Warm Device 3 50.8 29.6 80.7 19.1 Warm Colored EC deviceswith Optibronze Device 1 31.2 6.1 125.3 3.8 Neutral Device 2 23.2 5.9174.5 3.9 Neutral Device 3 24.4 5.9 142.8 4.2 Neutral

EXAMPLE 2 Fabrication of an Electrochromic Device (Device 4) WithTungsten Oxide Electrochromic Layer and With Vanadium OxideIntercalating Counterelectrode. These are Small Devices, Thus PriorDeposition of Busbars Such as Silver Frits is Not Required

[0117] A 3×3 inch (7.6 cm×7.6 cm) EC window device (Device 4) was madeusing TEC 15 (from Pilkington LOF, Toledo, Ohio). The tungsten oxidecoating, lithium tungstate (Li_(0.3)W)O_(x), was deposited, as describedearlier, on TEC 15 glass. This is not a reduced form of tungsten oxideas lithium is present as an oxide. The thickness of the fired coatingwas 350 nm. Another piece of similar sized TEC 15 was coated with avanadium oxide coating (counterelectrode). Both the electrodes in thecell store or intercalate ions. Both electrodes posses electrochromicproperties, but the doped tungsten oxide imparts stronger coloration.This substrate had two small holes (about {fraction (1/16)} of an inch(1.6 mm)) about 1.5 cm from two of its diagonal corners. The depositionof the vanadium oxide coating was also done by wet-chemical deposition.Weighing out and mixing the components in the following order made thecoating solution: 12 g of iso-propyl acetate, 3 g of vanadiumtriisopropoxide oxide and 1.77 g of 2-ethylhexanoic acid. The mixturewas left standing for 10 minutes before using. The coating was depositedby spin coating and then placed in an oven at 80° C. The coating wasfired up to 400° C. Preferred firing temperatures are in the range of300 to 500° C. However, if strengthened glass were used to make thesedevices, it is preferred that the firing temperatures be kept below 400°C., and more preferably below 350° C. The heating rate from roomtemperature was 10 C/minute and was kept at the temperature for 2 hours.The coatings were cooled to about 50° C. in the oven by turning it offand leaving overnight and then removed. The coating thickness was 170nm. This coating was also etched around its perimeter in a width ofabout 10 mm.

[0118] A cell was fabricated by dispensing an epoxy around the perimeterof one of the substrates. This epoxy contained 210 micrometer (diameter)spherical glass beads. The epoxy was dispensed on the etched area. Thesecond substrate was lowered onto this one while providing an offset ofabout 5 mm along one of the edges. Care was taken that the epoxy touchedboth the substrates in the etched area. Spacers provided a separation of210 micrometers between the two substrates to accommodate theelectrolyte. The preferred thickness of the electrolyte is between 37micrometers to about 5 mm. The epoxy was cured at elevated temperatures(typically in the range of 80 to 200° C.). Typical curing time isbetween 10 minutes to a few hours. On the conductive side of the offsetarea, a soldered busbar was deposited and connected to an electricalwire. The cell was filled with 1.0M lithium triflate and 0.05M Ferrocenein propylene carbonate (PC). All the liquids used to process the cellshould have low water content, preferably below 1000 parts per million,and more preferably below 100 parts per million. This was introducedthrough one of the two holes (fill port) in one of the substrates. Theholes were temporarily plugged with plastic inserts. A DC voltage of1.2V was applied to the cell with the tungsten oxide being negative forabout 2 minutes. The cell colored to a deep tint due to the reduction oftungsten oxide by lithium ion insertion. The solution was then flushedout of the cell. It was refilled with ethanol and flushed several times,and then the cell was filled by a solution of 1 molar lithium triflatein PC to clean out any residue. The cell was colored and bleachedcompletely several times (3 to 5 times) by applying −1.2V and +1.2V,with respect to the tungsten oxide. It is important to reverse potentialonce the cell reached a steady state transmission level. The cell wasagain flushed several times with ethanol and it was quickly placed underdry conditions, preferably in a glove box which has an inert atmosphere.

[0119] The cell is then filled with the electrolyte, which is typicallya dissociable salt in a medium. Preferred salts include lithiumtriflate, lithium methide and lithium trifuoromethanesulfonimide (tradename HQ115 available from 3M specialty Chemicals, St. Paul, Minn.).Preferred solvents are polar solvents such as sulfolane, methylsulfolane glyme, PC, gamma-butyro-lactone, etc. In this example 1.5Msalt in sulfolane was used. The components were dried so that theelectrolyte had a water content of less than 30 ppm. Typical saltconcentration is chosen from 0.1M to 3M. After this the two holes (fillports) are sealed. One may use UV curable or thermally curableadhesives. One may also use mechanical plugs followed by adhesives alongwith cover plates made out of metal, glass or plastic, this is alsodescribed in the U.S. Pat. No. 5,856,211 which is disclosed herein byreference. These plates may be used in addition to the mechanical plugsas described above. One may even use plates which may be bonded byultrasonic means. This method is described in greater detail later. Theelectrolyte can also contain water and oxygen scavengers; polymericthickeners (such as polymethylmethacrylate, polyethers such aspolyethylene and polypropylene oxides, fluorinated polymers such aspolyvinylidene fluoride sold under the trade name of Kynar (Elf Atochem,Philadelphia, Pa.); inorganic viscosity modifiers such as fumed silicaand other such inorganic fillers: UV stabilizers, other salts, colorantsand dyes, etc. In the final electrolyte one may even add a little ofreversible and/or non-reversible redox agents such as metallocenes,preferably ferrocene and its derivatives to restore the charge (e.g.,Lithium ions) as the device with an EC electrode and a counter-electrodeages. Typical concentration of the redox agent is lower than 0.05M, butpreferably lower than 0.005M. The addition of redox agents inelectrochromic cells with two ion insertion electrodes is described inU.S. Pat. No. 5,215,684 for EC cells consisting of specific electrodes,electrolytes and salts. This patent is incorporated herein by reference.The aforementioned patent does not, however, describe the addition ofthese materials in electrochromic cells with ion insertion electrodes ofmixed oxides, vanadium oxide containing counter electrodes and in cellscontaining electrolytes with either sulfolanes, lithiumtrifuoromethanesulfonimide and mixed salts, low water contents and withUV stabilizers.

[0120] As described above, a novel procedure was employed for reducingthe electrodes in a cell (or inserting ions in one of the electrodes)where a EC device is made with two opposing electrodes where bothfunction by ion insertion, in this case tungsten oxide and vanadiumoxide respectively. In a typical prior art process, one of theelectrodes is pre-reduced generally by an electrochemical process. Theseprocesses are difficult to control for uniform ion-intercalation,particularly with increasing device size. Further, once reduced, theelectrode is vulnerable to re-oxidation in further processing,particularly if it is handled under ambient conditions and more so atelevated temperatures such as seal curing or other steps. Further, thiskind of reduction could be expensive as large vats of electrochemicalmediums are required to reduce large substrates. In accordance with anaspect of the invention, it is preferred to complete the cell processingas much as possible before such reduction. In this example the cellcavity was fabricated before the reduction process was employed. Furthera liquid medium (e.g., propylene carbonate, sulfolane, etc.) containingat least one anodic and/or one cathodic redox material along with adissociable salt (e.g., lithium perchlorate, lithium triflate, etc.) wasinjected into the pre-fabricated cavity. One of the cell electrode wasreduced by applying a voltage. After reduction the medium was flushed.During the flushing process one may choose to continue to apply thepotential as well if there is an evidence of re-oxidation whileflushing. The second step described above was cleaning with ethanol. Inthis step other polar or non-polar solvents may also be used forcleaning, such as acetonitrile, propylene carbonate, hexane, etc., orone may even skip this process by simply introducing pressurizednitrogen and argon to flush the cell clean. The procedure describedabove is one of many that may be employed and one may even skip the stepwhere the cell is filled with an intermediate electrolyte and cycled afew times prior to the introduction of the final electrolyte. Forexample, in a simple process, one may simply flush the reducing mediumout using inert gases described above and fill the cell with the finalelectrolyte and seal. The solvent system used in the final electrolytemay be a mixture of sulfolane and its derivatives (e.g., methylsulfolane). Typically co-solvents to sulfolane are typically added up to50% of sulfolane. The electrolyte in this case was sulfolane with 1.5molar lithium trifuoromethanesulfonimide. Examples of other preferredadditives or alternatives are co-solvents methyl sulfolane, propylenecarbonate, a-butyrolactone, polyethylene glycol, glymes; preferred UVstabilizers are benzophenones and benzotriazoles, e.g., Uvinul 3000,Uvinul 3050 (from BASF, Mount Olive, N.J.) and Tinuvin 213 (CibaSpecialty Chemicals, White Plains, N.Y.); salts such as lithiumtriflate; and thickener additives such as polyethers (polyethyleneoxide/polypropylene oxide copolymer) and nano-particle inorganic oxidessuch as fumed silica, in situ polymerizable urethane monomers capable ofcrosslinking (typically an isocyanate terminated monomer, hydroxyterminated monomer and a tin catalyst). The concentration of each of theUV stabilizers and the polymeric and/or monomeric additives is typicallyless than 20 wt % and preferably less than 10 wt % of the solvents.

[0121] The reversible redox promoter in this case was a reversiblemetallocene, e.g., ferrocene and coboltocene or their derivatives. Inthis case tungsten oxide and vanadium oxide are used as the two opposingion-insertion electrodes with ferrocene as the redox promoter, but onecan choose any organic or inorganic which can reversibly intercalateions. Some prominent electrodes are molybdenum oxide, niobium oxide,Cerium-titanium oxide, Titanium-vanadium oxide, Niobium-vanadium oxideand so forth. A more extensive list of electrodes for EC devices is inpatent application Ser. No. 09/443,109.

[0122] One may even choose a non-reversible agent in the electrolytewhich will reduce the electrodes by being activated by temperatureand/or radiation such as UV. Such agents are typically non-reversible.This is explained in U.S. Pat. No. 5,780,160 which is incorporated byreference. One such agent to reduce the electrode is ascorbic acid.

[0123] During the fabrication of the device care was taken to usematerials in seals and the electrolyte so that electronic conductivitywas suppressed. The leakage current in these devices in the fullycolored state at 85° C. was difficult to measure with the instruments weused, as it was lower than 0.05 μA/cm². Leakage current means thecurrent required to keep a device in a required state of transmittance.When a EC device is colored to a desired set point, there is powerconsumed to color the device to this desired transmission and then thereis power consumed to keep the device at that level of transmittance. Theleakage current is related to the latter. Once the desired state isreached and the power source is removed the device discharges and thisis seen as a change in transmission. Thus to keep that level oftransmission there are two alternatives. In the first one the powersource is not removed so that continuous current is fed in to the deviceto compensate for the discharge. Alternatively, one can let the devicedischarge so that its transmission level changes (typically small enoughthat the user is unable to perceive) and then reapply power to bring itback to the desired state of transmittance. In this case the current isfed intermittently. In either case the feeding of charge is required,this charge is typically drained from the battery, or there is a leakageof charge from the battery. This leakage of charge will eventually drainthe battery. Thus to keep the battery drain low in a parked automobileand prolong battery life this leakage (or average leakage current, ifintermittent power is supplied) needs to be at a low desired number asgiven earlier. This leakage current should preferably be measured at thebattery. For intermittent powering of the electrochromic device thedischarge in the device can be measured e.g., by optical sensors orelectronically (such as open circuit potential of the cell). Another wayof specifying low leakage current also is to specify change in devicetransmittance when the power is removed (open circuit).

[0124] Once the device was colored, it changed by less than 1% photopictransmission in 15 minutes when stored at 85° C. without any voltagebeing applied and changed by about another 0.5% in the next 35 minutes.It is preferred to have devices that change less then 5% of theirtransmission when stored at 85° C. for 15 minutes without any externalapplication of potential (open circuit). In the counterelectrodedevices, one of the important variables to get low leakage is to keepthe water content lower than 2000 ppm, preferably lower than 100 ppm andmost preferably as low as 10 ppm. Photopic Color L* C* h (% T)perception Bleached EC device Device 4 79.6 6.3 173.2 57.8 neutralColored EC device Device 4 51.9 27.3 148.4 13.8 green Cover GlassesGL-20 46.7 0.94 243.2 15.8 neutral GL-35 65.8 1.6 125.3 35.0 neutralOptibronze 58.9 23.2 72.8 26.9 warm Bleached EC device with GL-20 Device4 35.6 3.6 186.8 9.1 neutral Colored EC device with GL-20 Device 4 20.714.6 146.8 2.1 neutral/green Bleached EC device with GL-35 Device 4 51.55.2 162.9 20.3 neutral Colored EC device with GL-35 Device 4 32.3 19.8145.1 4.7 neutral/green Bleached EC device with Optibronze Device 4 45.518.4 84.3 15.5 warm Colored EC device with Optibronze Device 4 25.6 20.9114.7 3.5 warm/neutral

EXAMPLE 3 Preparation of a EC Device (Device 5a,b) Which Uses LiMnNiOCounterelectrode

[0125] A solution to deposit LiMnNiO electrode was prepared as follows.1.56 g of lithium methoxide was dissolved in 50 ml of distilled ethanol.Separately 9.28 g of Nickel(ll)ethylhexanoate (78% in 2 ethylhexanoicacid) and 18.81 g of manganese(ll)2-ethylhexanoate (40% in mineralspirits) were mixed and stripped off in a rotary evaporator (@90° C.) ofabout 8.91 g of volatiles. After this 8.91 g of ethanol was added. Thetwo solutions were then mixed together. After they dissolved in eachother, a uniform phase was obtained which was used as a coatingsolution. The substrate (TEC15) was coated by spinning and then fired upto 450° C. under conditions similar to the vanadium oxide describedabove. The coating thickness was 180 to 200 nm depending on the spinningconditions. A cell (Device 5a) was prepared with tungsten oxide as theother electrode as described above in the case of vanadium oxide. Thecell was filled with 1.5M lithium perchlorate in PC and sealed. Thiscell did not require any pre-reduction because the lithium from theLiMnNiO electrode could be extracted as Li⁺ ions upon applying acoloring voltage to the cell and inserting the extracted lithiumreversibly into the tungsten oxide. This has many advantages in terms ofprocessing of the EC devices. Particularly, if one needs to laminate thetwo substrates with a pre-formed electrolyte film, then one can easilyhandle these substrates in ambient conditions. A 3×3 inch sample wascolored at 1.8 volts and bleached at −1.8 volts. The sample colored from59% photopic to 8% photopic in 54 seconds and it bleached to theoriginal value in 71 seconds. It was also found that the bleach rate wasnot affected when the bleach potential was lowered to −0.1V. Anothersample (Device 5b) was made in the same size to measure color. Thesample in the bleach state had 56.5% photopic transmittance. It wascolored to 17.5% photopic transmittance and its color was measuredagain. The table below describes the details. Photopic Color L* C* h (%T) perception Bleached EC device Device 5b 79.9 21.0 91.9 56.5 warmColored EC device Device 5b 48.6 15.5 129.7 17.3 neutral Cover GlassesGL-20 46.7 0.94 243.2 15.8 Neutral GL-35 65.8 1.6 125.3 35.0 NeutralOptibronze 58.9 23.2 72.8 26.9 Warm Bleached EC device with GL-20 Device5b 35.7 11.5 96.7 8.9 neutral Colored EC device with GL-20 Device 5b19.5 8.8 129.4 2.9 neutral Bleached EC device with GL-35 Device 5b 51.716.2 95.2 19.9 warm Colored EC device with GL-35 Device 5b 28.9 11.5130.3 5.8 neutral Bleached EC device with Optibronze Device 5b 46.4 31.276.9 15.6 warm Colored EC device with Optibronze Device 5b 24.9 18.893.6 4.4 warm

EXAMPLE 4 Ultrasonic Sealing of Plug Holes

[0126] This is a novel sealing method to close the plug holes (fillports) which is described in detail in the already filed patentapplication DE 100 06 199.0. The welding requires a cover or a plug tobe placed on top of the plughole or inside the plughole. This cover (orplug) is then bonded on to the glass by fusing its surface with theglass surface. An ultrasonic oscillator rapidly provides the energyrequired to do this. The equipment employs a press to place the coverwith a certain force covering the hole and contacting the substrate,transducers, ultrasonic generator and controller. An equipment supplierfor such a system is Telesonic Ultrasonics (Bridgeport, N.J.) who sellssuch ultrasonic welding systems. The oscillations are typicallyrotational or translational with respect to the surface normal. In caseof the present EC device the holes are plugged by covering them withthin foils or plates. These foils could be made out of a single materialor be alloys and composites. Some of the preferred materials are Al, Cu,Pt, Au, Ti and stainless steel. Preferred alloys are nickel containingalloys. For example Ni/Fe alloys and Ni/Fe/Co alloys such as Kovar whichhave thermal expansion similar to glass. The difference between thelinear thermal expansion coefficient of glass and the metal cap shouldbe less than 5×10⁻⁶ cm/cm/C when measured between 25 to 300° C.Preferably, even if the thermal expansion of the two are close it ispreferred that the alloy has a slightly lower shrinkage than glass sothat on the glass surface close to the edge of the metal cap compressiveforces are experienced. This will keep the joints less prone to stressfailure.

[0127] Some of the Ni/Fe containing alloys are Invar, Alloy 52, Alloy48, Alloy 42 and Alloy 42-6. These can be obtained from Ed Fagen Inc(Los Alamitos, Calif.). The table below gives the thermal expansion ofthese alloys between 30 and 300° C., for a comparison the expansioncoefficient of soda-lime glass between 0 and 300° C. is 9.2×10⁻⁶ cm/cm/°C. and the contraction coefficient from the annealing point to 25° C. is114. Alloy Kovar Alloy 52 Alloy 48 Alloy 46 Alloy 42 Alloy 42-6 InvarExpansion 5.1 × 10⁻⁶ 10.2 × 10⁻⁶ 8.8 × 10⁻⁶ 7.5 × 10⁻⁶ 4.0-4.7 × 10⁻⁶8.2 × 10⁻⁶ 4.92 × 10⁻⁶ Coeff (cm/cm/° C.)

[0128] A preferred thickness of the alloys used for plugging the holesis less than 300 micrometers. These could be coated with other metals,oxide layers or polymeric layers. When used with oxide and polymericlayers, the coated side preferably faces the plughole. This layerprovides additional inertness, as this will likely be in contact withthe electrolyte. Also during the fusion process the polymeric materialin contact with the surface is burned away so that proper glass to metalbond is obtained. Another preferred composite material is surfaceanodized Al foil. One may also coat more inexpensive materials such asAl and Cu with gold and platinum to provide the inertness. One may alsouse adhesion promotion layers between these dissimilar materials to getgood bonding between them. Most of the plugholes sealed were about 1.5to 3 mm in diameter. The foil size was about 1 sq. cm in area with atypical thickness of 50 to 250 micrometers. The foil was pressed againstthe substrate with a force of 1000 to 10,000 N and then the ultrasonicenergy was applied at 10-50 kHz. The welding time was between 0.1 to 1second and no further post-processing was needed. This method hasseveral advantages over the method described earlier where adhesives oradhesively bonded cover slides are used to plug the holes. Some of theseadvantages are:

[0129] Hermetic sealing, in particular gas-tightness (e.g. impermeableto He, O₂, CO₂, water vapor, etc.)

[0130] Short operating time and no post-processing is required (lowercost)

[0131] Wide material choice for the cover, including materials which areinert towards other cell components

[0132] Long-term durability and low thermal stresses

[0133] No Exposure or Entrapment of Environment of the CellcontentsWhile Sealing

[0134] Thus this method and the advantages are applicable to the sealingof any chromogenic device.

EXAMPLE 5 Device Showing Both EC Behavior and a Heating Phenomena Usingthe Same Transparent Conductor Which is Used to Power the EC Device

[0135] A 11×11 inch (28 cm×28 cm) EC window device (Device 1) was madeusing Indium Tin Oxide (ITO, 15 ohms/square, Applied Films Corp,Longmont, Colo.) as one electrode and TCO12 (from AFG, Kingsport, Tenn.)as the other electrode. The tungsten oxide coating, a lithium tungstate(Li_(0.5)W)O_(x), was deposited on the ITO glass. (This is not a reducedform of tungsten oxide as lithium is present as an oxide.) The thicknessof the fired coating was 580 nm. The coating was fired in a humidatmosphere followed by a heat treatment up to 250° C. Details ofdeposition and precursor used can be found in comparative example 1 ofPCT 97/05791, the disclosure of which is incorporated by referenceherein. The coating was then etched from the perimeter area (about 10 mmin width) of the substrate. A cell was fabricated by dispensing an epoxyaround the perimeter of one of the substrates and the conductive sidesfacing each other. This epoxy contained 300 micrometer (diameter)spherical glass beads. The spacers provided a separation of 300micrometers between the two substrates, which would be the thickness ofthe electrolyte. The preferred thickness of the electrolyte is between37 micrometers to about 5 mm. The epoxy was dispensed on the etchedarea. The second TEC15 175 substrate was lowered onto the firstsubstrate 174 while providing an offset of about 5 mm along two edges ofeach substrate as shown in FIG. 12. The epoxy was cured at elevatedtemperatures (typically in the range of 80 to 200° C.). Typical curingtime is between 10 minutes to a few hours. The upper substrate 175 hadtwo 1.6 mm diameter holes along its diagonal about 10 mm away from thecorners. The electrolyte was injected through one of these holes to fillthe cavity with the electrolyte. The electrolyte contained (all weight%) 0.35% ferrocene, 10.5%LiCF₃SO₃, 48.9%PC, 32.6% sulfolane and 7.65% ofpolymethylmethacrylate with a molecular weight of about 540,000. Theholes were then sealed with Teflon plugs followed by rectangular glasscover slides 171 and 172, which were bonded by a UV curable adhesive(shown in FIG. 12). The sealing is done by first priming the hole areaand a 1 mm thick (about 1 cm square) glass cover-plate with a primerbased on Dow Corning (MI) Z6030 silane. The cover-plates are then gluedusing a UV curable adhesive to block the holes. Another thermal curingepoxy is then used to seal the sides of the cover-plates to furtherenhance the environmental barrier. Alternatively, the plug area may besealed with metallic caps, as described in Example 4.

[0136] On each substrate edge which was protruding out, a conductivebusbar was soldered, and then connected to wires A,B, C and D as shownin FIG. 12. Wires A and C were pigtailed together, and B and D werepigtailed together. When A+C were connected to a Positive terminal of aDC power supply of 1.2V, and Band D were connected to the negativeterminal, the device colored and when the polarity was reversed (and thepotential decreased to −0.6V), the device bleached to the originalvalue. Then, all the wires were disconnected from each other and fromthe power supply. When wires A and C were respectively connected to apositive and a negative terminal of a DC power supply of 12V, a currentflowed through the circuit and the surface temperature of the glassincreased.

EXAMPLE 6 Fabrication of an Electrochromic Device (Device 4) WithTungsten Oxide Electrochromic Layer and With Vanadium OxideIntercalating Counterelectrode. This Device Shows a Shade Band Conceptby Controlling the Resistance Between the Electrodes

[0137] A 11×11 inch (28 cm×28 cm) EC window device 180 was made usingTEC 15 and TEC 8 (from Pilkington LOF, Toledo, Ohio) as shown in FIG.13. The glass substrates 181 and 182 are designated S and the conductivecoatings 183 and 184 as TC. TEC 15 was used to coat tungsten oxide 185and TEC8 for the counterelectrode 186. Each of the transparentsubstrates have a pair of busbar 187 and 188 running parallel to the twoopposite edges as shown. These busbars 187 and 188 are connected to theelectrical wires 189-192. The electrochromic coating EC 185 is tungstenoxide and the counterelectrode CE 186 is vanadium oxide. These coatedsubstrates are separated by an electrolyte E 193. The tungsten oxidecoating, lithium tungstate (Li_(0.5)W)O_(x), was deposited, as describedearlier in example 5, on one of the TEC 15 glass. The thickness of thefired coating was 580 nm. Another piece of similar sized TEC 15 wascoated with a vanadium oxide coating (counterelectrode). Both theelectrodes in the cell store or intercalate ions. Both electrodespossess electrochromic properties, but the doped tungsten oxide impartsstronger coloration. This substrate had two small holes (about {fraction(1/16)} of an inch (1.6 mm)) about 1.5 cm from two of its diagonalcorners. The substrate are used to assemble an empty cavity as describedin the earlier example. These holes are not shown in FIG. 13.

[0138] The cell (or cavity) is first flushed by high purity nitrogen(chromatography grade). A potential of −0.5V is applied to the twoelectrodes before the reducing electrolyte is introduced in the cavity.This positive electrode is tungsten oxide. The reducing liquidelectrolyte is 0.05M ferrocene and 1.0 molar lithium triflate in amixture of 50% sulfolane and 50% acetonitrile by weight. All the liquidsused to process the cell should have low water content, preferably below1000 parts per million, and more preferably below 100 parts per million.This reducing electrolyte introduced through one of the two holes (fillport) in one of the substrates while the above potential is applied.After filling, the polarity of the potential is reversed and it isincreased to 1.3V. This potential is applied for two minutes till thecell colors uniformly. The cell is bleached by reversing this potential(1.3V with CE being negative), and after the cell bleaches, while thepotential is still being applied, the cell is drained of the reducingelectrolyte. Alternatively, the electrolyte could also be drained in thecolored state. The cell is now filled with cleaning solvent to get ridof the residues from the prior process, which is typically acetonitrileand sulfolane in equal amounts by weight. The cleaning solvent isdrained and then preferably the cell is filled by another cleaningsolvent which can be acetonitrile only. The cell is dried by pumping thehigh purity nitrogen. The final electrolyte is introduced that may havemonomers which could be polymerized in-situ by heat, UV, visble, IR ormicrowave radiation. As described in the above example, the fill holesare sealed after the filling process.

[0139] The electrolyte, consisted of a dissociable salt in a medium.Preferred salts include lithium triflate, lithium methide and lithiumtrifuoromethanesulfonimide (trade name HQ115 available from 3M specialtyChemicals, St. Paul, Minn.). Preferred solvents are polar solvents suchas sulfolane, methyl sulfolane glyme, PC, gamma-butyro-lactone, etc. Inthis example 1.5M salt in sulfolane was used. A UV stabilizer was alsoadded to the electrolyte. The components were dried so that theelectrolyte had a water content of less than 30 ppm. Typical saltconcentration is chosen from 0.1M to 3M.

[0140] A coloring voltage is applied between A and C of 1.2V (with thetungsten oxide side being negative), and all the other terminal wiresfrom the cell are in open and not connected to the power circuit. Thecell starts coloring from the busbar which is powered, and thecoloration proceeds in a parralel line to the powered busbar till thewhole cell is colored.

[0141] The foregoing description for the purposes of simplicity hasconcentrated on chromogenic devices having electrochromic layers.However it will be apparent to those skilled in the art that chromogenicdevices employing no electrochromic layers but instead employing anelectrolyte having at least one anodic and one cathodic compoundtogether with salts and UV stabilizers, etc, or which use particlessuspended in the electrolyte (suspended particle devices) which changeorientation under the applied electric field rather than electrochromiclayers can be made. Further and other modifications may be made by thoseskilled in the art without, however, departing from the spirit and scopeof the invention.

What is claimed is:
 1. A transparent chromogenic assembly, comprising:a. a pair of facing transparent substrates defining a cavity forenclosing an electrolyte medium; facing surfaces of the substrates eachhaving a conductive transparent coating, said conductive coating of atleast one of said substrates being interrupted along a demarcation linehaving a thickness of at least 0.01 mm to insulate contiguous areas onopposite sides of said line from one another, the conductive coating ofat least one of the substrates being overlain with an electrochromiclayer; and b. a set of busbars deposed toward the periphery of each ofsaid areas.
 2. A transparent chromogenic assembly according to claim 1further including an adhesive spacer element interposed between saidsubstrates.
 3. A transparent chromogenic assembly according to claim 2wherein said spacer element is adapted to insulate a portion of saidbusbars from exposure to said electrolyte.
 4. A transparent chromogenicassembly according to claim 1 wherein each set of said busbars isindividually energizeable to effect a color change through a respectiveone of said areas.
 5. A transparent chromogenic assembly according toclaim 1 wherein said electrolyte exhibits chromogenic properties.
 6. Atransparent chromogenic assembly according to claim 1 wherein a portionof said busbars is provided with a passivation coating to insulate saidportion from said electrolyte.
 7. A transparent chromogenic assemblyaccording to claim 1 wherein a portion of each set of busbars extendsfrom the facing surface of a respective substrate over an edge thereofto form an electrical connector.
 8. A transparent chromogenic assemblyaccording to claim 1 wherein each set of said busbars adjoins at leasttwo sides of a respective one of said areas.
 9. A transparentchromogenic assembly according to claim 1 wherein said transparentconductive coating comprises a material selected from the groupconsisting of a doped oxide of tin and indium-tin oxide.
 10. Atransparent chromogenic assembly according to claim 1 wherein at leastone of said substrates is either tempered, strengthened or tempered andstrengthened.
 11. A transparent chromogenic assembly according to claim2 wherein said electrochromic layer comprises at least one transitionmetal oxide.
 12. A transparent chromogenic assembly according to claim11 wherein said one transition metal oxide comprises tungsten oxide. 13.A transparent chromogenic assembly according to claim 1 having acounterelectrode layer on a surface of said substrates facing thesurface containing said electrochromic layer.
 14. A transparentchromogenic assembly according to claim 13 wherein said counterelectrodemixture contains an oxide selected from the group consisting of lithiumoxide, nickel oxide, vanadium oxide and manganese oxide.
 15. Atransparent chromogenic assembly according to claim 1 wherein saidelectrolyte medium has at least one dissociable salt and one UVstabilizer.
 16. A transparent chromogenic assembly according to claim 1wherein said electrolyte medium includes a solvent or plasticizercontaining a sulfolane.
 17. A transparent chromogenic assembly accordingto claim 16 wherein said electrolyte medium is converted to a solidmaterial by incorporation of a material selected from the groupconsisting of polymers, in-situ polymerizable monomers and nano-particalinorganic oxides.
 18. A transparent chromogenic assembly according toclaim 16 wherein said electrolyte is thickened by incorporation of amaterial selected from the group consisting of polymers andnano-particle inorganic oxides.
 19. A transparent chromogenic panel foruse on the exterior of a transportation vehicle exposed to the weatherrequiring an average current less than 10 μA/cm² of active area tomaintain any desired state of transmission at a temperature of up to 85°C. for a duration of at least 8 hours.
 20. A transparent electrochromicpanel according to claim 19 having inorganic electrochromic andcounterelectrodes defining said active area, said electrodes beingselected principally from the transition metal oxides, such as tungstenoxide and vanadium oxide, respectively, and having a liquid or solidpolymer matrix electrolyte containing a sufficient amount of a sulfolaneto act as a solvent and/or plasticizer for said electrolyte and a watercontent lower than 2000 ppm, preferably as low as 10 ppm.
 21. Atransparent chromogenic panel according to claim 19 which imparts to theperceiver a warm or neutral perceived color comprising: an activecomponent layer and a passive component layer in which the activecomponent layer is selected from the group consisting of electrochromic,liquid crystal, user-controllable-photochromic, polymer-dispersed-liquidcrystal or suspended particle devices and the passive component layer isselected from the group consisting of substrates or covers for theactive layer, said active and said passive layers being chosen so thatthe color and the transmissivity of the passive layer accommodates therange of color change in the active layer to maintain the transmittedcolor of the panel in a warm or neutral shade, where warm colors on theL*C*h color sphere scale correspond to C having a value between 15 and45; h having a value between 100 and 20, and where the value of Ldepends on the darkness of the glass or preferred degree of photopictransmission desired.
 22. A transparent electrochromic panel as in claim21 wherein the neutral colors correspond to C less than 15, preferablyless than 5, and h between 0 and 360, while L can be any number yieldingthe desired photopic transmission.
 23. A transparent electrochromicpanel according to claim 21 wherein said active component layercomprises: a. a pair of facing glass substrates separated by a spacer todefine a cavity for an electrolyte medium, facing surfaces of saidsubstrates each having a conductive transparent coating, said conductivecoating being interrupted on at least one of said substrates to defineindividual areas, the conductive coating of at least one of thesubstrates being overlain with an electrochromic layer; b. a set ofindividually energizable busbars deposed toward the periphery of each ofsaid areas to effect a respective color change therethrough.
 24. Amethod of making an electrochromic panel having a pair of facing glasssubstrates forming a cell cavity for an electrolyte; facing surfaces ofthe substrates each having a conductive transparent coating where eachof these faces is coated with ion-intercalatable electrodes, at leastone of which is electrochromic, wherein one of said electrodes isreduced after the cell cavity is formed, comprising the steps of: (a)filling said cavity with a reducing fluid medium containing at least oneof an anodic and a cathodic redox material; (b) applying a voltage atleast once to reduce one of said electrodes; (c) flushing the reducingliquid from the cavity; and (d) filling said cavity with theelectrolyte.
 25. The method of claim 24, wherein said reducing fluidmedium includes at least one of a dissociable salt and an acid.
 26. Themethod of claim 24 wherein said redox material is a metallocene.
 27. Themethod of claim 26 wherein said metallocene is selected from the groupconsisting of ferrocene, a ferrocene derivative, cobaltocene and amixture thereof.
 28. The method of claim 25 wherein said dissociablesalt is selected from the group consisting of lithium, sodium andpotassium.
 29. The method of claim 24 wherein said one of saidsubstrates is provided with an electrochromic layer the composition ofwhich includes at least an oxide of tungsten.
 30. The method of claim 24wherein at least one of said ion-intercalatable electrodes contains atleast one oxide selected from the group consisting of vanadium oxide,nickel oxide and manganese oxide.
 31. The method of claim 24 wherein theelectrolyte contains each of the following: at least one dissociablesalt; at least one UV stabilizer; at least one polar solvent; and awater content less then 2000 ppm.
 32. The method of claim 31 wherein thepolar solvent is selected from the group consisting of sulfolane, methylsulfolane, propylene carbonate, gamma-butyrolactone and polyethyleneglycol.
 33. The method of claim 24 wherein said electrolyte is convertedto a solid material by incorporation of a material selected from thegroup consisting of polymers, in-situ polymerizable monomers andnano-partical inorganic oxides.
 34. The method of claim 24 wherein saidelectrolyte is thickened by incorporation of a material selected fromthe group consisting of polymers and nano-partical inorganic oxides. 35.The method of claim 24, wherein said reducing fluid is forced out ofsaid cell cavity by a flushing medium consisting of at least one of apolar solvent, non-polar solvent or an inert gas.
 36. The method ofclaim 24, wherein said step of flushing is repeated one or more timesprior to filling said cavity with said electrolyte.
 37. A transparentchromogenic device with controlled variation of an area of coloration,said device comprising: (a) a pair of facing transparent substratesdefining a cavity enclosing an electrolyte medium; (b) facing surfacesof the substrates each having a conductive transparent coating; (c) eachconductive transparent coating having at least two bus bars in contacttherewith, wherein each of said two bus bars contacting each conductivetransparent coating are positioned in a spaced-apart relationshipdefining a portion of said device in which the area of coloration ofsaid device is variably controlled; and (d) a controller that provides ameans for controlling the area of coloration by varying a voltage dropacross said device.
 38. The transparent chromogenic device according toclaim 37, further comprising an electrochromic layer disposed on atleast one of the conductive transparent coatings.
 39. The transparentchromogenic device according to claim 37, wherein said electrolytemedium is electrochromic.
 40. The transparent chromogenic deviceaccording to claim 37, wherein said means for controlling the area ofcoloration includes a switch for applying a voltage between a first oneof said two bus bars contacting a first one of the conductivetransparent coatings and an opposing first one of said two bus barscontacting a second one of the conductive transparent coatings.
 41. Thetransparent chromogenic device according to claim 40, wherein said meansfor controlling the area of coloration includes a resistor communicatingbetween a second one of said two bus bars contacting the first one ofthe conductive transparent coatings and an opposing second one of saidtwo bus bars contacting the second one of the conductive transparentcoatings.
 42. The transparent chromogenic device according to claim 41,wherein said resistor is a variable resistor.
 43. A transparentchromogenic device having both coloration and heating capability, saiddevice comprising: (a) a pair of facing transparent conductors defininga cavity enclosing an electrolyte medium; (b) a transparent substrate onan outer face of at least one of said transparent conductors; (c) atleast one transparent conductor having at least two bus bars in contacttherewith, wherein said two bus bars contacting said transparentconductor are positioned in a spaced-apart relationship defining aportion of said device which may be colored or heated; and (d) acontroller that provides a means to selectively apply a voltage to colorsaid device or heat said device.
 44. The transparent chromogenic deviceaccording to claim 43, wherein said device is comprised of twotransparent substrates each on an outer face of each conductor.
 45. Thetransparent chromogenic device according to claim 43, further comprisingan electrochromic layer disposed on at least one of the transparentconductors.
 46. The transparent chromogenic device according to claim43, wherein said electrolyte medium is chromogenic.
 47. The transparentchromogenic device according to claim 43, wherein said controllerincludes an electrical circuit that is selectively controlled to (i)cause coloration of said device by creating a voltage potential betweenat least one of said two bus bars contacting a first one of thetransparent conductors and at least one bus bar contacting a second oneof the transparent conductors and (ii) cause heating of said device bycreating a voltage potential between at least said two bus barscontacting at least one of said transparent conductors.
 48. A solarpowered chromogenic window system comprising: (a) a chromogenic glazing;(b) a solar power source for providing power to said chromogenicglazing; and (c) either a central control system or user controlledinterface that is in wireless communication with said solar powersource.
 49. A front-side window of a vehicle having at least achromogenic portion comprising: (a) a pair of facing transparentconductors with an electrolyte medium disposed therebetween in an areaof said window defined by a look-through portion of said window for adriver of said vehicle looking at a side-view mirror of said vehicle;(b) a transparent substrate on an outer face of at least one of saidtransparent conductors; and (c) a set of busbars disposed toward atleast a portion of the periphery of said area of each conductor.
 50. Thefront-side window according to claim 49, wherein said window iscomprised of two transparent substrates each on an outer face of eachconductor.
 51. The front-side window according to claim 49, furthercomprising an electrochromic layer disposed on at least one of thetransparent conductors.
 52. The front-side window according to claim 49,wherein said electrolyte medium is electrochromic.
 53. A chromogenicglazing having improved wireless signal transmission capability, saidglazing comprising: (a) a pair of facing transparent conductors defininga cavity enclosing an electrolyte medium; and (b) a transparentsubstrate on an outer face of at least one of said transparentconductors, wherein said improvement resides in the absence of thetransparent conductors in a defined area or the inclusion of at leastone optical transceiver in said device.
 54. The chromogenic glazingaccording to claim 53, wherein said glazing is comprised of twotransparent substrates each on an outer face of each conductor.
 55. Thechromogenic glazing according to claim 53, further comprising anelectrochromic layer disposed on at least one of the transparentconductors.
 56. The chromogenic glazing according to claim 53, whereinsaid electrolyte medium is chromogenic.
 57. A method of controlling theuniformity of appearance of a glazing comprised of a plurality ofchromogenic panels, said method comprising the steps of: (a) receivingimage data from at least one optical sensor individually scanning saidchromogenic panels; (b) using said image data to adjust the powersupplied to each individual chromogenic panel to a predetermined lighttransmission value.
 58. The method according to claim 57, wherein saidpredetermined light transmission value for each chromogenic panel issubstantially equivalent.
 59. The method according to claim 57, whereinsaid predetermined light transmission value for each chromogenic panelis set to create a desired image in said glazing.
 60. A chromogenicglazing system comprising: (a) at least one chromogenic glazingcommunicating with a control system; (b) a photosensor that communicateswith said control system; and (c) a temperature sensor that communicateswith said control system, wherein data received by said control systemfrom said photosensor and temperature sensor is processed to select apredetermined amount of power to be supplied to said chromogenicglazing.
 61. The chromogenic glazing according to claim 60, wherein saidtemperature sensor determines a temperature of an interior compartmentof a vehicle or building.
 62. The chromogenic glazing according to claim60, wherein said temperature sensor determines a temperature of ambientconditions outside a vehicle or building.
 63. A chromogenic windowcomprising: (a) a non-polarizing chromogenic layer disposed between twotransparent conductors; (b) a transparent substrate on an outer face ofat least one of said transparent conductors; and (c) at least onecoating or layer selected from the group consisting of: (i) at least onepolarizing filter; (ii) a self-cleaning coating; and (iii) a hydrophiliccoating.
 64. The chromogenic window according to claim 63, wherein saidwindow is comprised of two transparent substrates each on an outer faceof each conductor.
 65. The chromogenic window according to claim 63,wherein at least one of said coating or layer is laminated to saidchromogenic window.
 66. The chromogenic window according to claim 63,wherein said window further comprises at least one of an IR or UVblocking layer.
 67. A chromogenic device comprising: (a) a pair offacing conductors defining a cavity enclosing an electrolyte mediumwherein at least one of said conductors is transparent; and (b) atransparent substrate on an outer face of at least one of saidtransparent conductors, wherein said substrate is a glass substratecomprised of phosphate or is laminated with a phosphate containingmaterial.
 68. The chromogenic device according to claim 67, wherein bothconductors are transparent and said device is comprised of twotransparent substrates each on an outer face of each conductor.
 69. Thechromogenic device according to claim 67, further comprising anelectrochromic layer disposed on an inner face of at least one of saidtransparent conductors.
 70. A chromogenic device comprising: (a) a pairof facing conductors defining a cavity enclosing an electrolyte medium,wherein at least one of said conductors is transparent; and (b) atransparent substrate on an outer face of at least one of saidtransparent conductors, wherein said substrate is a glass substratecomprised of a rare earth oxide selected from the group consisting ofneodymium oxide, erbium oxide, ytterbium oxide or mixtures thereof. 71.The chromogenic device according to claim 70, wherein both conductorsare transparent and said device is comprised of two transparentsubstrates each on an outer face of each conductor.
 72. The chromogenicdevice according to claim 70, further comprising an electrochromic layerdisposed on an inner face of at least one of said transparentconductors.
 73. A method of sealing fill holes in a chromogenic assemblyhaving a glass substrate comprising the step of covering each of saidholes with a metal cap, wherein the difference between the linearthermal expansion coefficient of the glass substrate and the metal capis less than 5×10⁻⁶ cm/cm/° C. when measured between 25 and 300° C. 74.A chromogenic assembly comprising: (a) a pair of facing conductorsdefining a cavity enclosing an electrolyte medium wherein at least oneof said conductors is transparent; and (b) a transparent substrate on anouter face of at least one of said transparent conductors, wherein saidtransparent substrate is a strengthened substrate or a strengthenedtransparent substrate is laminated to said transparent substrate. 75.The chromogenic assembly according to claim 74, wherein both conductorsare transparent and said device is comprised of two transparentsubstrates each on an outer face of each conductor.
 76. The chromogenicassembly according to claim 75, wherein both transparent substrates arestrengthened transparent substrates.
 77. A chromogenic windowcomprising: (a) chromogenic layer disposed between two transparentconductors; (b) a transparent substrate on an outer face of at least oneof said transparent conductors; and (c) at least one laminated layer onan outer surface of said window selected from the group consisting of:(i) a glass breakage sensing layer; (ii) an antenna layer; (iii) aheater layer; or (iv) a bullet proof layer.